DNA–RNA hybrid(DRH) plays important roles in many biological processes. Here, we use a thermodynamic theory to analyze the free energy and unpeeling properties of the overstretching transition for the DRH molecule an...DNA–RNA hybrid(DRH) plays important roles in many biological processes. Here, we use a thermodynamic theory to analyze the free energy and unpeeling properties of the overstretching transition for the DRH molecule and compare the results with double-helix DNA. We report that the RNA strand of DRH is easier to get unpeeled than the DNA strand while the difficulty in unpeeling the double helix DNA lies in between. We also investigate the sequence effect, such as GC content and purine content, on the properties of unpeeling the DRH. Further, to study the temperature effect, the forcetemperature phase diagram of DRH and DNA are calculated and compared. Finally, using a kinetic model, we calculate the force–extension curves in the DRH stretching and relaxation process under different pulling rates and temperatures. Our results show that both pulling rate and temperature have important influences on the stretching and relaxation kinetics of unpeeling the DRH. Putting all these results together, our work provides a comprehensive view of both the thermodynamics and kinetics in DRH overstretching.展开更多
Background: A dandelion is a common plant with a global growth distribution that has been used as a medicinal and food with no adverse effects. Purpose: In this article, the products and effects of dandelions are revi...Background: A dandelion is a common plant with a global growth distribution that has been used as a medicinal and food with no adverse effects. Purpose: In this article, the products and effects of dandelions are reviewed to help further in-depth studies and develop more products derived from dandelions in the future. Method: The literature about dandelion in various databases such as Pubmed is searched. Results: Dandelions have many effects, such as virus inhibition, anti-tumor activity, nutritional value, anti-aging, potential as a vaccine and alleviation of heat stress. The mechanism underlying these effects is analyzed and it was found that dandelions were regulated by RNA or DNA. Conclusion: As a medicinal and food, dandelions are safe and have many effects. Many products derived from dandelions have been developed. The metabolic regulation is related with ribonucleic acid or possibly deoxynucleic acid. Further in-depth studies should be conducted on the regulation of dandelions through RNA or DNA. There will likely be more products derived from dandelions in the future.展开更多
With the help of model experiments, we are able to offer a detailed proposal for the inhibition of DNA duplication and no inhibition of RNA viral infectivity. As a backbone, we introduced methyl phosphotriester (MPTE)...With the help of model experiments, we are able to offer a detailed proposal for the inhibition of DNA duplication and no inhibition of RNA viral infectivity. As a backbone, we introduced methyl phosphotriester (MPTE). Duplex formation according to the traditional Watson and Crick base-pairing: [(MPTE)<sub>n−1</sub> DNA] * DNA and [(MPTE)<sub>n−1</sub> DNA] * RNA, where n = number of DNA and RNA bases. However, in the latter case, inhibition is obtained by reduction of the number of MPTE linkages, as is confirmed with model experiments and under biological conditions with micro (mi)RNA substrates. The latter results have recently been published. One or more single MPTEs are disseminated over different places of DNA without neighbour MPTEs (Prof. Wen-Yih Chen and his group, Taiwan).展开更多
目的观察龙葵碱对S180和H22荷瘤小鼠肿瘤细胞DNA和RNA的影响。方法将S180和H22荷瘤小鼠分为龙葵碱37.50、18.75、9.37 m g/kg组、阴性对照组和环磷酰胺(30 m g/kg)组,各组sc给药。利用激光共聚焦扫描显微镜,分别测定各组肿瘤细胞中的DNA...目的观察龙葵碱对S180和H22荷瘤小鼠肿瘤细胞DNA和RNA的影响。方法将S180和H22荷瘤小鼠分为龙葵碱37.50、18.75、9.37 m g/kg组、阴性对照组和环磷酰胺(30 m g/kg)组,各组sc给药。利用激光共聚焦扫描显微镜,分别测定各组肿瘤细胞中的DNA和RNA。结果龙葵碱(37.50、18.75 m g/kg)组对S180和H22小鼠肿瘤细胞RNA和DNA的比值均有明显的降低作用。结论龙葵碱降低S180和H22小鼠肿瘤细胞RNA和DNA的比值可能是其抗肿瘤作用机制之一。展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.11674403)the Young Scientists Fund of the National Natural Science Foundation of China(Grant No.31700809)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.18lgzd16)the Open Fund of the State Key Laboratory of Optoelectronic Materials and Technologies,Sun Yat-sen University
文摘DNA–RNA hybrid(DRH) plays important roles in many biological processes. Here, we use a thermodynamic theory to analyze the free energy and unpeeling properties of the overstretching transition for the DRH molecule and compare the results with double-helix DNA. We report that the RNA strand of DRH is easier to get unpeeled than the DNA strand while the difficulty in unpeeling the double helix DNA lies in between. We also investigate the sequence effect, such as GC content and purine content, on the properties of unpeeling the DRH. Further, to study the temperature effect, the forcetemperature phase diagram of DRH and DNA are calculated and compared. Finally, using a kinetic model, we calculate the force–extension curves in the DRH stretching and relaxation process under different pulling rates and temperatures. Our results show that both pulling rate and temperature have important influences on the stretching and relaxation kinetics of unpeeling the DRH. Putting all these results together, our work provides a comprehensive view of both the thermodynamics and kinetics in DRH overstretching.
文摘Background: A dandelion is a common plant with a global growth distribution that has been used as a medicinal and food with no adverse effects. Purpose: In this article, the products and effects of dandelions are reviewed to help further in-depth studies and develop more products derived from dandelions in the future. Method: The literature about dandelion in various databases such as Pubmed is searched. Results: Dandelions have many effects, such as virus inhibition, anti-tumor activity, nutritional value, anti-aging, potential as a vaccine and alleviation of heat stress. The mechanism underlying these effects is analyzed and it was found that dandelions were regulated by RNA or DNA. Conclusion: As a medicinal and food, dandelions are safe and have many effects. Many products derived from dandelions have been developed. The metabolic regulation is related with ribonucleic acid or possibly deoxynucleic acid. Further in-depth studies should be conducted on the regulation of dandelions through RNA or DNA. There will likely be more products derived from dandelions in the future.
文摘With the help of model experiments, we are able to offer a detailed proposal for the inhibition of DNA duplication and no inhibition of RNA viral infectivity. As a backbone, we introduced methyl phosphotriester (MPTE). Duplex formation according to the traditional Watson and Crick base-pairing: [(MPTE)<sub>n−1</sub> DNA] * DNA and [(MPTE)<sub>n−1</sub> DNA] * RNA, where n = number of DNA and RNA bases. However, in the latter case, inhibition is obtained by reduction of the number of MPTE linkages, as is confirmed with model experiments and under biological conditions with micro (mi)RNA substrates. The latter results have recently been published. One or more single MPTEs are disseminated over different places of DNA without neighbour MPTEs (Prof. Wen-Yih Chen and his group, Taiwan).
文摘目的观察龙葵碱对S180和H22荷瘤小鼠肿瘤细胞DNA和RNA的影响。方法将S180和H22荷瘤小鼠分为龙葵碱37.50、18.75、9.37 m g/kg组、阴性对照组和环磷酰胺(30 m g/kg)组,各组sc给药。利用激光共聚焦扫描显微镜,分别测定各组肿瘤细胞中的DNA和RNA。结果龙葵碱(37.50、18.75 m g/kg)组对S180和H22小鼠肿瘤细胞RNA和DNA的比值均有明显的降低作用。结论龙葵碱降低S180和H22小鼠肿瘤细胞RNA和DNA的比值可能是其抗肿瘤作用机制之一。
