A new C-glycosylflavone, named panzhihuacycaside (1), was isolated from the leaves of Cycas panzhihuaensis L. Zhou et S. Y. Yang (Cycadaceae) along with 2,3-dihydrohinokiflavone (2), 5,5',7,7', 4',4'&#...A new C-glycosylflavone, named panzhihuacycaside (1), was isolated from the leaves of Cycas panzhihuaensis L. Zhou et S. Y. Yang (Cycadaceae) along with 2,3-dihydrohinokiflavone (2), 5,5',7,7', 4',4''-hexahydroxy-(2',8')-biflavone (3), vanillic acid (4), P-sitosterol (5) and daucosterol (6). Their structures were elucidated by spectral and chemical evidence.展开更多
BACKGROUND Gastric cancer is one of the most common and deadly malignancies worldwide.Despite recent medical progress, the 5-year survival rate of gastric cancer is still unsatisfactory. 5-fluorouracil(5-Fu) is one of...BACKGROUND Gastric cancer is one of the most common and deadly malignancies worldwide.Despite recent medical progress, the 5-year survival rate of gastric cancer is still unsatisfactory. 5-fluorouracil(5-Fu) is one of the first-line antineoplastic treatments for gastric cancer, as it can effectively induce cancer cell apoptosis.However, the effect of 5-Fu is limited due to drug resistance of the malignant tumor. Previous studies have reported that Sotetsuflavone from Cycas revoluta Thunb. can markedly suppress lung cancer cell proliferation by apoptosis,though its effect on gastric cancer remains unknown.AIM To investigate the inhibitory effect of Cycas revoluta Thunb. and to determine whether it can overcome gastric cancer cell drug resistance to 5-Fu.METHODS Cell viability was examined to determine whether the natural extract of Cycas revoluta Thunb. induced gastric cancer cell death. The half-maximal effective concentration and the half-maximal lethal concentration were calculatede.Wound-healing and transwell assays were performed to examine gastric cancer cell motility. Clonogenic assays were performed to investigate the synergistic effects of Cycas revoluta Thunb. with 5-Fu, and apoptotic bodies were detected by Hoechst staining. Western blotting was performed to examine the expression of related proteins and to investigate the molecular mechanism of Cycas revoluta Thunb.-induced cancer cell apoptosis. The expressions of proteins, including mammalian target of rapamycin(mTOR) and p-AKT, were detected in different combinations of treatments for 48 h, then analyzed by ECL detection.RESULTS Gastric cancer cells were more sensitive to the natural extract of Cycas revoluta Thunb. compared to normal gastric epithelial cells, and the extract effectively inhibited gastric cancer cell migration and invasion. The extract improved the anti-cancer effect of 5-Fu by enhancing the chemosensitization of gastric cancer cells. Extract plus 5-Fu further reduced the expression of the drug-resistancerelated proteins p-AKT and mTOR after 48 h compared to 5-Fu alone. Compared to 5-Fu treatment alone, mTOR and p-AKT expression was significantly reduced by about 50% and 75%, respectively. We also found that the natural extract of Cycas revoluta Thunb. further increased 5-Fu-induced gastric cancer cell apoptosis. Expression of apoptosis-related protein X-linked inhibitor of apoptosis protein and apoptosis inducing factor were significantly reduced and increased,respectively, in the 5-Fu-resistant gastric cancer line SGC-7901/R treated with extract plus 5-Fu, while the expression of survivin did not change.CONCLUSION The natural extract of Cycas revoluta Thunb. effectively inhibited gastric cancer cell growth and enhanced the anti-cancer effect of 5-Fu through the AKT-mTOR pathway.展开更多
Cycas panzhihuaensis L.Zhou & S.Y.Yang(Cycadaceae) is an endangered gymnosperm species endemic to the dry-hot valley of the Jinsha River basin in southwest China.Although the wild C.panzhihuaensis population from ...Cycas panzhihuaensis L.Zhou & S.Y.Yang(Cycadaceae) is an endangered gymnosperm species endemic to the dry-hot valley of the Jinsha River basin in southwest China.Although the wild C.panzhihuaensis population from Panzhihua Cycad Natural Reserve is well protected and its genetic diversity has been well assessed,the genetic characteristics of populations outside the nature reserve,which face larger risks of extinction,remain unknown.Furthermore,the population genetics and historical dynamics of this endemic and endangered species have not been examined across its entire range.In this study,to analyze the genetic diversity,phylogeographical structure and demographic history of C.panzhihuaensis from all its seven known locations,we sequenced and compared molecular data from chloroplastic DNA(psbA-trnH,psbM-trnD,and trnS-trnG),single-copy nuclear genes(PHYP,AC5,HSP70,and AAT) from 61 individuals,as well as 11 nuclear micro satellite loci(SSR) from 102 individuals.We found relatively high genetic diversity within populations and high genetic differentiation among populations of C.panzhihuaensis,which is consistent with the patterns of other Asian inland cycads.Although no significant phylogeographical structure was detected,we found that small and unprotected populations possess higher genetic diversity and more unique haplotypes,which revises our understanding of diversity within this species and deserves due attention.Analysis of demographic dynamics suggest that human activity might be the key threat to C.panzhihuaensis.Based on the genetic characterization of C.panzhihuaensis,we propose several practical guidelines for the conservation of this species,especially for the populations with small sizes.展开更多
Geological activities and climate oscillations during the Quaternary period profoundly impacted the distribution of species in Southwest China. Some plant species may be harbored in refugia, such as the dry-hot valley...Geological activities and climate oscillations during the Quaternary period profoundly impacted the distribution of species in Southwest China. Some plant species may be harbored in refugia, such as the dry-hot valleys of Southwest China. Cycas chenii X. Gong & W. Zhou, a critically endangered cycad species, which grows under the canopy in subtropical evergreen broad-leaved forests along the upstream drainage area of the Red River, is endemic to this refugium. In this study, 60 individuals of C. chenii collected from six populations were analyzed by sequencing two chloroplast intergenic spacers(cp DNA:psb A-trn H and trn L-trn F) and two nuclear genes(PHYP and RBP-1). Results showed high genetic diversity at the species level, but low within-population genetic diversity and high interpopulation genetic differentiation. A Bayesian phylogenetic tree based on cp DNA showed that five chloroplast haplotypes were clustered into two clades, which corresponds to the division of the western and eastern bank of the Red River. These data indicate a possible role for the Red River as a geographic barrier to gene flow in C. chenii.Based on our findings, we propose appropriate in situ and ex situ conservation strategies for C. chenii.展开更多
The so-called “megasporophylls” of Ginkgoales, Coniferales, and Gnetales have been proven metamorphosed shoots, making “megasporophyll” of Cycas the last one resembling a leaf. Why and how it is so in Cycas (the m...The so-called “megasporophylls” of Ginkgoales, Coniferales, and Gnetales have been proven metamorphosed shoots, making “megasporophyll” of Cycas the last one resembling a leaf. Why and how it is so in Cycas (the most ancient seed plant dated back to the Palaeozoic) become key questions because their answers are hinged with the fates of several hypotheses in botany. Here, we performed a controlled developmental experiment on the ovulate parts (megasporophylls) in a single strobilus of Cycas sexseminifera. By removing the neighboring ones, two of the ovulate parts were left isolated spatially from others, in contrast to others left intact. A half-year-long continuous observation indicates that the isolated ovulate parts change their ovule arrangement from initial pinnate into helical pattern, while the intact ones in the same strobilus remain pinnate as usual. Since all ovulate parts are in the same strobilus and controlled by the same genome in this case and the only difference is lack of pressure from neighbors for the isolated ones, the changes in ovule orientation and ovulate part morphology can only be attributed to the lack of mechanical pressure among the ovulate parts. Therefore, we conclude that mechanical pressure, not genes, controls the morphology of ovulate parts and contributes to the leaf-like ovulate part morphology in Cycas. This conclusion cautions previous superficial interpretations of plant morphology.展开更多
A normalized full-length cDNA library was constructed from the coralloid roots of Cycas debaoensis by the DSN （duplex-specific nuclease） normalization method combined with the SMART （Switching Mechanism At 5＇ end ...A normalized full-length cDNA library was constructed from the coralloid roots of Cycas debaoensis by the DSN （duplex-specific nuclease） normalization method combined with the SMART （Switching Mechanism At 5＇ end of the RNA Transcript） technique. The titer of the original cDNA library was about 1.5 × 10^6 cfu·mL^-1 and the average insertion size was about 1 kb with a high recombination rate （97%）. The 5011 high-quality expressed sequence tags （ESTs） were obtained from 5393 randomly picked cDNA clones. Clustering and assembly of ESTs resulted in 2984 unique sequences, consisting of 618 contigs and 2366 singlets. EST sequence annotation revealed that 2333 and 1901 unigenes were functionally anno- tated in the NCBI non-redundant database and Swiss-Prot protein database, respectively. Functional analysis demonstrated that 1495 （50.1%） unigenes were associated with 4082 Gene Ontology （GO） terms. A total of 847 unigenes were grouped into 22 Cluster of Orthologous Groups （COG） functional categories. Based on the EST dataset, 22 ESTs that encoded putative receptor-like protein kinase （RLK） genes were screened. Furthermore, a total of 94 simple sequence repeats （SSRs） were discovered, of which 20 loci were successfully amplified in C debaoensis. This study is the first EST analysis for the coralloid roots of C debaoensis and provides a valuable genomic resource for novel gene discovery, gene expression and comparative genomics, conservation and management studies as well as applications in C debaoensis and related cycad species.展开更多
文摘A new C-glycosylflavone, named panzhihuacycaside (1), was isolated from the leaves of Cycas panzhihuaensis L. Zhou et S. Y. Yang (Cycadaceae) along with 2,3-dihydrohinokiflavone (2), 5,5',7,7', 4',4''-hexahydroxy-(2',8')-biflavone (3), vanillic acid (4), P-sitosterol (5) and daucosterol (6). Their structures were elucidated by spectral and chemical evidence.
文摘BACKGROUND Gastric cancer is one of the most common and deadly malignancies worldwide.Despite recent medical progress, the 5-year survival rate of gastric cancer is still unsatisfactory. 5-fluorouracil(5-Fu) is one of the first-line antineoplastic treatments for gastric cancer, as it can effectively induce cancer cell apoptosis.However, the effect of 5-Fu is limited due to drug resistance of the malignant tumor. Previous studies have reported that Sotetsuflavone from Cycas revoluta Thunb. can markedly suppress lung cancer cell proliferation by apoptosis,though its effect on gastric cancer remains unknown.AIM To investigate the inhibitory effect of Cycas revoluta Thunb. and to determine whether it can overcome gastric cancer cell drug resistance to 5-Fu.METHODS Cell viability was examined to determine whether the natural extract of Cycas revoluta Thunb. induced gastric cancer cell death. The half-maximal effective concentration and the half-maximal lethal concentration were calculatede.Wound-healing and transwell assays were performed to examine gastric cancer cell motility. Clonogenic assays were performed to investigate the synergistic effects of Cycas revoluta Thunb. with 5-Fu, and apoptotic bodies were detected by Hoechst staining. Western blotting was performed to examine the expression of related proteins and to investigate the molecular mechanism of Cycas revoluta Thunb.-induced cancer cell apoptosis. The expressions of proteins, including mammalian target of rapamycin(mTOR) and p-AKT, were detected in different combinations of treatments for 48 h, then analyzed by ECL detection.RESULTS Gastric cancer cells were more sensitive to the natural extract of Cycas revoluta Thunb. compared to normal gastric epithelial cells, and the extract effectively inhibited gastric cancer cell migration and invasion. The extract improved the anti-cancer effect of 5-Fu by enhancing the chemosensitization of gastric cancer cells. Extract plus 5-Fu further reduced the expression of the drug-resistancerelated proteins p-AKT and mTOR after 48 h compared to 5-Fu alone. Compared to 5-Fu treatment alone, mTOR and p-AKT expression was significantly reduced by about 50% and 75%, respectively. We also found that the natural extract of Cycas revoluta Thunb. further increased 5-Fu-induced gastric cancer cell apoptosis. Expression of apoptosis-related protein X-linked inhibitor of apoptosis protein and apoptosis inducing factor were significantly reduced and increased,respectively, in the 5-Fu-resistant gastric cancer line SGC-7901/R treated with extract plus 5-Fu, while the expression of survivin did not change.CONCLUSION The natural extract of Cycas revoluta Thunb. effectively inhibited gastric cancer cell growth and enhanced the anti-cancer effect of 5-Fu through the AKT-mTOR pathway.
基金This work was supported by the National Key R&D Program of China(2017YF0505200).The authors thank Fangming Zhang for her assistance with plant sampling,and Xiuyan Feng,Rui Yang and Yujuan Zhao for their help and discussion of data analyses.
文摘Cycas panzhihuaensis L.Zhou & S.Y.Yang(Cycadaceae) is an endangered gymnosperm species endemic to the dry-hot valley of the Jinsha River basin in southwest China.Although the wild C.panzhihuaensis population from Panzhihua Cycad Natural Reserve is well protected and its genetic diversity has been well assessed,the genetic characteristics of populations outside the nature reserve,which face larger risks of extinction,remain unknown.Furthermore,the population genetics and historical dynamics of this endemic and endangered species have not been examined across its entire range.In this study,to analyze the genetic diversity,phylogeographical structure and demographic history of C.panzhihuaensis from all its seven known locations,we sequenced and compared molecular data from chloroplastic DNA(psbA-trnH,psbM-trnD,and trnS-trnG),single-copy nuclear genes(PHYP,AC5,HSP70,and AAT) from 61 individuals,as well as 11 nuclear micro satellite loci(SSR) from 102 individuals.We found relatively high genetic diversity within populations and high genetic differentiation among populations of C.panzhihuaensis,which is consistent with the patterns of other Asian inland cycads.Although no significant phylogeographical structure was detected,we found that small and unprotected populations possess higher genetic diversity and more unique haplotypes,which revises our understanding of diversity within this species and deserves due attention.Analysis of demographic dynamics suggest that human activity might be the key threat to C.panzhihuaensis.Based on the genetic characterization of C.panzhihuaensis,we propose several practical guidelines for the conservation of this species,especially for the populations with small sizes.
基金supported by the United Fund of the NSFCthe Yunnan Natural Science Foundation(Grant No.U1136602 to X.G.)
文摘Geological activities and climate oscillations during the Quaternary period profoundly impacted the distribution of species in Southwest China. Some plant species may be harbored in refugia, such as the dry-hot valleys of Southwest China. Cycas chenii X. Gong & W. Zhou, a critically endangered cycad species, which grows under the canopy in subtropical evergreen broad-leaved forests along the upstream drainage area of the Red River, is endemic to this refugium. In this study, 60 individuals of C. chenii collected from six populations were analyzed by sequencing two chloroplast intergenic spacers(cp DNA:psb A-trn H and trn L-trn F) and two nuclear genes(PHYP and RBP-1). Results showed high genetic diversity at the species level, but low within-population genetic diversity and high interpopulation genetic differentiation. A Bayesian phylogenetic tree based on cp DNA showed that five chloroplast haplotypes were clustered into two clades, which corresponds to the division of the western and eastern bank of the Red River. These data indicate a possible role for the Red River as a geographic barrier to gene flow in C. chenii.Based on our findings, we propose appropriate in situ and ex situ conservation strategies for C. chenii.
文摘The so-called “megasporophylls” of Ginkgoales, Coniferales, and Gnetales have been proven metamorphosed shoots, making “megasporophyll” of Cycas the last one resembling a leaf. Why and how it is so in Cycas (the most ancient seed plant dated back to the Palaeozoic) become key questions because their answers are hinged with the fates of several hypotheses in botany. Here, we performed a controlled developmental experiment on the ovulate parts (megasporophylls) in a single strobilus of Cycas sexseminifera. By removing the neighboring ones, two of the ovulate parts were left isolated spatially from others, in contrast to others left intact. A half-year-long continuous observation indicates that the isolated ovulate parts change their ovule arrangement from initial pinnate into helical pattern, while the intact ones in the same strobilus remain pinnate as usual. Since all ovulate parts are in the same strobilus and controlled by the same genome in this case and the only difference is lack of pressure from neighbors for the isolated ones, the changes in ovule orientation and ovulate part morphology can only be attributed to the lack of mechanical pressure among the ovulate parts. Therefore, we conclude that mechanical pressure, not genes, controls the morphology of ovulate parts and contributes to the leaf-like ovulate part morphology in Cycas. This conclusion cautions previous superficial interpretations of plant morphology.
基金supported by the Grant(201522)from Shenzhen Urban Management
文摘A normalized full-length cDNA library was constructed from the coralloid roots of Cycas debaoensis by the DSN （duplex-specific nuclease） normalization method combined with the SMART （Switching Mechanism At 5＇ end of the RNA Transcript） technique. The titer of the original cDNA library was about 1.5 × 10^6 cfu·mL^-1 and the average insertion size was about 1 kb with a high recombination rate （97%）. The 5011 high-quality expressed sequence tags （ESTs） were obtained from 5393 randomly picked cDNA clones. Clustering and assembly of ESTs resulted in 2984 unique sequences, consisting of 618 contigs and 2366 singlets. EST sequence annotation revealed that 2333 and 1901 unigenes were functionally anno- tated in the NCBI non-redundant database and Swiss-Prot protein database, respectively. Functional analysis demonstrated that 1495 （50.1%） unigenes were associated with 4082 Gene Ontology （GO） terms. A total of 847 unigenes were grouped into 22 Cluster of Orthologous Groups （COG） functional categories. Based on the EST dataset, 22 ESTs that encoded putative receptor-like protein kinase （RLK） genes were screened. Furthermore, a total of 94 simple sequence repeats （SSRs） were discovered, of which 20 loci were successfully amplified in C debaoensis. This study is the first EST analysis for the coralloid roots of C debaoensis and provides a valuable genomic resource for novel gene discovery, gene expression and comparative genomics, conservation and management studies as well as applications in C debaoensis and related cycad species.
