As contamination is one of important factors to Panax notoginseng quality and safety. Saponin is one of important compounds with the medicinal values of P. notoginseng. The impact of soil As on production of saponin o...As contamination is one of important factors to Panax notoginseng quality and safety. Saponin is one of important compounds with the medicinal values of P. notoginseng. The impact of soil As on production of saponin of P. notoginseng knew very little. This study was performed to determine content and heterogeneity of saponins from P. notoginseng and its mechanisms upon treatments with different concentration levels of As in soil. Plants of P. notoginseng were treated with arsenic [As (V)] at 0, 20, 80, 140, 20 and 260 mg/kg concentration levels which were supplied as sodium arsenate (Na<sub>3</sub>AsO<sub>4</sub>)<sub>.</sub> These experimental plants were grown in shade condition in a greenhouse. Plants were harvested at vigorous vegetative growth and fruit ripening stages, separately. Effects of As treatments on saponin content, and heterogeneity of monomers in the mixtures of notoginesenosides and ginsenosides, enzymatic activity and gene expression level of squalene synthetase were determined for rhizome and main root tissues. Results show that:(1) Of all the As treatments from the lowest to the highest concentration levels, the As content in both rhizome and main roots from As-treated plants was within the standard level for superior products derived from P. notoginseng. The content of notoginsenosides from all tissues except the main roots at fruit ripening stage, was 5% higher than the standard level specified in the Chinese Pharmacopoeia;(2) The treatment of As at 20 mg/kg led to an 3.5% - 183.9% increases in total notoginesenosides content in rhizome and main roots, respectively. Treatments with the highest As concentration at 260 mg/kg<sup> </sup>resulted in a significant decline in total notoginsenosides content, and lower enzymatic activity and gene expression levels of squalene synthetase;(3) Under As treatment conditions, the ratio of Rb1/Rg1 decreased but the ratio of (Rb1 + Rg1)/R1 increased in both rhizomes and main roots. Conclusively, this study demonstrated that low As concentration (20 - 80 mg/kg) treatments resulted in higher notoginsenoside content in P. notoginseng. However, treatments with high As concentrations had an adverse effect. The repression in the synthesis of notoginsenoside and interruption of the conversion process from propanaxadiol into propanaxatriol are responsible for more heterogeneous monomer mixtures and low notoginsenoside content. For plants treated with the highest As concentration of 260 mg/kg, both gene expression and enzymatic activities of squalene synthetase were greatly repressed thus leading to a significantly low saponin content in rhizome and main root tissues.展开更多
OBJECTIVE To explore the role of hypoxic inducible factor-1α(HIF-1α) in the proliferation and apoptosis of pancreatic cancercells under hypoxic conditions.METHODS A cassette encoding small interference RNA (siRNA)ta...OBJECTIVE To explore the role of hypoxic inducible factor-1α(HIF-1α) in the proliferation and apoptosis of pancreatic cancercells under hypoxic conditions.METHODS A cassette encoding small interference RNA (siRNA)targeting HIF-1α mediated by recombinant adeno-associated virus(rAAV) was constructed, giving rAAV-siHIF. rAAV-siHIF or rAAV-hrGFP was transfected into exponentially growing MiaPaCa2cells under hypoxic conditions. Then, the expression of HIF-1αmRNA and protein, the proliferation and apoptosis of MiaPaCa2cells were examined, using real-time PCR, Western Blot, MTT andTUNEL, respectively.RESULTS Under hypoxic conditions, rAAV-siHIF inhibited theexpression of HIF-1α mRNA and protein in MiaPaCa2 cells. At thesame time, rAAV-siHIF decreased MiaPaCa2 cell proliferation andinduced apoptosis. However, rAAV-hrGFP had no effect on theexpression of HIF-1α as well as the proliferation and apoptosis ofMiaPaCa2 cells under hypoxic conditions.CONCLUSION Under hypoxic conditions, HIF-1α plays a keyrole in the proliferation of MiaPaCa2 cells, and inhibition of HIF-1α expression can lead to MiaPaCa2 cell apoptosis.展开更多
Southeastern Tibet is one of the most glaciated regions on the Tibetan Plateau both at present and during the Quaternary. Numerical dating of glacial deposits has allowed the establishment of a provisional chronology ...Southeastern Tibet is one of the most glaciated regions on the Tibetan Plateau both at present and during the Quaternary. Numerical dating of glacial deposits has allowed the establishment of a provisional chronology of Quaternary glacial fluctuations in this region, with the oldest glaciation(Guxiang Glaciation) occurring in marine oxygen isotope stage 6(MIS-6).During our recent field investigations, a morphostratigraphically older lateral moraine than that of the Guxiang Glaciation has been first identified, which is ~500–600 m above the Guxiang Glaciation moraine and discontinuously preserved on valley shoulders in the Bodui Zangbo River valley, eastern Nyainqêntanglha Range in southeastern Tibet. Considering the moraine is best preserved at Nitong Village, here we name the glacier advance which deposited the moraine as "Nitong Glaciation". Using electron spin resonance(ESR) technique, we dated the Nitong Glaciation moraine to 506.3±60.4 ka. Taking into account the age error and climatic conditions, we consider it most likely that the Nitong Glaciation occurred during MIS-12, although it might had happened sometime earlier.展开更多
文摘As contamination is one of important factors to Panax notoginseng quality and safety. Saponin is one of important compounds with the medicinal values of P. notoginseng. The impact of soil As on production of saponin of P. notoginseng knew very little. This study was performed to determine content and heterogeneity of saponins from P. notoginseng and its mechanisms upon treatments with different concentration levels of As in soil. Plants of P. notoginseng were treated with arsenic [As (V)] at 0, 20, 80, 140, 20 and 260 mg/kg concentration levels which were supplied as sodium arsenate (Na<sub>3</sub>AsO<sub>4</sub>)<sub>.</sub> These experimental plants were grown in shade condition in a greenhouse. Plants were harvested at vigorous vegetative growth and fruit ripening stages, separately. Effects of As treatments on saponin content, and heterogeneity of monomers in the mixtures of notoginesenosides and ginsenosides, enzymatic activity and gene expression level of squalene synthetase were determined for rhizome and main root tissues. Results show that:(1) Of all the As treatments from the lowest to the highest concentration levels, the As content in both rhizome and main roots from As-treated plants was within the standard level for superior products derived from P. notoginseng. The content of notoginsenosides from all tissues except the main roots at fruit ripening stage, was 5% higher than the standard level specified in the Chinese Pharmacopoeia;(2) The treatment of As at 20 mg/kg led to an 3.5% - 183.9% increases in total notoginesenosides content in rhizome and main roots, respectively. Treatments with the highest As concentration at 260 mg/kg<sup> </sup>resulted in a significant decline in total notoginsenosides content, and lower enzymatic activity and gene expression levels of squalene synthetase;(3) Under As treatment conditions, the ratio of Rb1/Rg1 decreased but the ratio of (Rb1 + Rg1)/R1 increased in both rhizomes and main roots. Conclusively, this study demonstrated that low As concentration (20 - 80 mg/kg) treatments resulted in higher notoginsenoside content in P. notoginseng. However, treatments with high As concentrations had an adverse effect. The repression in the synthesis of notoginsenoside and interruption of the conversion process from propanaxadiol into propanaxatriol are responsible for more heterogeneous monomer mixtures and low notoginsenoside content. For plants treated with the highest As concentration of 260 mg/kg, both gene expression and enzymatic activities of squalene synthetase were greatly repressed thus leading to a significantly low saponin content in rhizome and main root tissues.
基金supported by a grant from Nature Science Foundation of Tianjin,China(No.05YFSYSF01300).
文摘OBJECTIVE To explore the role of hypoxic inducible factor-1α(HIF-1α) in the proliferation and apoptosis of pancreatic cancercells under hypoxic conditions.METHODS A cassette encoding small interference RNA (siRNA)targeting HIF-1α mediated by recombinant adeno-associated virus(rAAV) was constructed, giving rAAV-siHIF. rAAV-siHIF or rAAV-hrGFP was transfected into exponentially growing MiaPaCa2cells under hypoxic conditions. Then, the expression of HIF-1αmRNA and protein, the proliferation and apoptosis of MiaPaCa2cells were examined, using real-time PCR, Western Blot, MTT andTUNEL, respectively.RESULTS Under hypoxic conditions, rAAV-siHIF inhibited theexpression of HIF-1α mRNA and protein in MiaPaCa2 cells. At thesame time, rAAV-siHIF decreased MiaPaCa2 cell proliferation andinduced apoptosis. However, rAAV-hrGFP had no effect on theexpression of HIF-1α as well as the proliferation and apoptosis ofMiaPaCa2 cells under hypoxic conditions.CONCLUSION Under hypoxic conditions, HIF-1α plays a keyrole in the proliferation of MiaPaCa2 cells, and inhibition of HIF-1α expression can lead to MiaPaCa2 cell apoptosis.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41771065, 42071088, 41271077 and 41371080)。
文摘Southeastern Tibet is one of the most glaciated regions on the Tibetan Plateau both at present and during the Quaternary. Numerical dating of glacial deposits has allowed the establishment of a provisional chronology of Quaternary glacial fluctuations in this region, with the oldest glaciation(Guxiang Glaciation) occurring in marine oxygen isotope stage 6(MIS-6).During our recent field investigations, a morphostratigraphically older lateral moraine than that of the Guxiang Glaciation has been first identified, which is ~500–600 m above the Guxiang Glaciation moraine and discontinuously preserved on valley shoulders in the Bodui Zangbo River valley, eastern Nyainqêntanglha Range in southeastern Tibet. Considering the moraine is best preserved at Nitong Village, here we name the glacier advance which deposited the moraine as "Nitong Glaciation". Using electron spin resonance(ESR) technique, we dated the Nitong Glaciation moraine to 506.3±60.4 ka. Taking into account the age error and climatic conditions, we consider it most likely that the Nitong Glaciation occurred during MIS-12, although it might had happened sometime earlier.
