In the paper, related research and progress of molecular clock hypothesis were summarized, including definition of molecular clock, supporting proofs, contro- versy, significance and perfection, application and accomp...In the paper, related research and progress of molecular clock hypothesis were summarized, including definition of molecular clock, supporting proofs, contro- versy, significance and perfection, application and accompanying challenges.展开更多
Objective: To investigate the role of collagen IV and PAS positive substancesecreted by tumor cells in vasculogenic mimicry (VM) and the effects of VM on tumor cells expressingVEGF. Methods: 158 cases of bi-direction ...Objective: To investigate the role of collagen IV and PAS positive substancesecreted by tumor cells in vasculogenic mimicry (VM) and the effects of VM on tumor cells expressingVEGF. Methods: 158 cases of bi-direction differential malignant tumor specimens withparaffin-embedded were enrolled into our study and made tissue microarray which were dual-stainedwith CD31-PAS and stained with collagen IV. The difference of the areas and distribution withpattern surrounded by between CD31 and PAS positive respectively were identified via grid-counting,as well as the difference of VEGF expression with VE absent and present. Results: The basementmembrane of VM was both PAS and collagen IV positive. VEGF expression in the bi-directiondifferential malignant tumor was higher VM-absent than VM-present and the difference wasstatistically significance in malignant melanoma and alveolar rhabdomyosarcoma (P 【 0.05).Conclusion: PAS positive substance and collagen IV compose the wall of VE and VE could provide theoxygen and nutrition for tumor growth and progression.展开更多
In this study, the relationship between major meteorological factors and tobacco chemical components in different altitudes of Yongde County, Lincang Region of Yunnan Province was studied using correlation analysis an...In this study, the relationship between major meteorological factors and tobacco chemical components in different altitudes of Yongde County, Lincang Region of Yunnan Province was studied using correlation analysis and path analysis methods.The results showed that there was a difference on meteorological factors in different altitudes, causing different impacts on chemical components of flue-cured tobacco; contents of nicotine and total nitrogen decreased with the rising of altitude, conversely, total sugar and reducing sugar contents increased with the rising trend of altitude, and the differences on the contents of potassium （K） and chlorine（CI）, and the ratio of K to CI in different altitudes were not significant, at the altitude of 1 250-1 450 m, each chemical component indicator was better. The correlation between main meteorological factors and conventional chemical components of tobacco leaves was as follows： contents of reducing sugar and total sugar increased with the increase of rainfall and relative humidity, and decreased with the increase of sunshine duration; nicotine content increased with the increase of accumulated temperature and sunshine duration; total nitrogen （N） content increased with the increase of daily mean temperature and accumulated temperature; sugar-alkali ratio increased with the increase of rainfall. Path analysis showed that the direct effect of sunshine duration on reducing sugar and total sugar of tobacco leaves was faint, but the indirect effect was obvious; meanwhile, the direct and indirect effects of it on nicotine and total N were the greatest.展开更多
Pseudogene and fibrin peptide which has rapid evolve speed and good stability are used in this study to determine the divergence date among groups.Through calculating the evolutionary rate of hemoglobin α chain,γ ch...Pseudogene and fibrin peptide which has rapid evolve speed and good stability are used in this study to determine the divergence date among groups.Through calculating the evolutionary rate of hemoglobin α chain,γ chain in vertebrate（including birds and mammals）,it is concluded that the evolutionary rate of hemoglobin α chain,γ chain is not invariable.It shows different evolutionary rates in different periods,that is,faster in early evolution stage and relatively slow in later stage.展开更多
Actin depolymerizing factor （ADF）, highly conserved in all eukaryotic cells, is a low molecular mass of actin-binding protein, which plays a key role in modulating the polymerizing and depolymerizing of the actin fi...Actin depolymerizing factor （ADF）, highly conserved in all eukaryotic cells, is a low molecular mass of actin-binding protein, which plays a key role in modulating the polymerizing and depolymerizing of the actin filaments. Four cDNAs （designated GhADF2, GhADF3, GhADF4, and GhADF5, respectively） encoding ADF proteins were isolated from cotton （Gossypium hirsutum） fiber cDNA library. GhADF2 cDNA is 705 bp in length and deduces a protein with 139 amino acids. GhADF3 cDNA is 819 bp in length and encodes a protein of 139 amino acids. GhADF4 cDNA is 804 bp in length and deduces a protein with 143 amino acids. GhADF5 cDNA is 644 bp in length and encodes a protein of 141 amino acids. The molecular evolutionary relationship of these genes was analyzed by means of bioinformatics. GhADF2 is closely related to GhADF3 （99% identity） and PetADF2 （89% identity）. GhADF4 is closely related to AtADF6 （78% identity）, and GhADF5 is closely related to AtADF5 （83% identity）. These results demonstrated that the plant ADF genes are highly conserved in structure. RT-PCR analysis showed that GhADF2 is predominantly expressed in fiber, whereas, GhADF5 is mainly expressed in cotyledons. On the other hand, it seems that GhADF3 and GhADF4 have no tissue specificity. Expression levels of different ADF genes may vary considerably in the same cell type, suggesting that they might be involved in regulating tissue development of cotton and the each ADF isoform may diverge to form the functional difference from the other ADFs during evolution.展开更多
基金Supported by Hunan Education Reform ProjectEducation Reform Project of Hunan University of Humanities,Science and Technology(RKJGY1101)~~
文摘In the paper, related research and progress of molecular clock hypothesis were summarized, including definition of molecular clock, supporting proofs, contro- versy, significance and perfection, application and accompanying challenges.
基金This work was partially supported by a grant from the National Natural Science Foundation of China (No. 30370378)
文摘Objective: To investigate the role of collagen IV and PAS positive substancesecreted by tumor cells in vasculogenic mimicry (VM) and the effects of VM on tumor cells expressingVEGF. Methods: 158 cases of bi-direction differential malignant tumor specimens withparaffin-embedded were enrolled into our study and made tissue microarray which were dual-stainedwith CD31-PAS and stained with collagen IV. The difference of the areas and distribution withpattern surrounded by between CD31 and PAS positive respectively were identified via grid-counting,as well as the difference of VEGF expression with VE absent and present. Results: The basementmembrane of VM was both PAS and collagen IV positive. VEGF expression in the bi-directiondifferential malignant tumor was higher VM-absent than VM-present and the difference wasstatistically significance in malignant melanoma and alveolar rhabdomyosarcoma (P 【 0.05).Conclusion: PAS positive substance and collagen IV compose the wall of VE and VE could provide theoxygen and nutrition for tumor growth and progression.
文摘In this study, the relationship between major meteorological factors and tobacco chemical components in different altitudes of Yongde County, Lincang Region of Yunnan Province was studied using correlation analysis and path analysis methods.The results showed that there was a difference on meteorological factors in different altitudes, causing different impacts on chemical components of flue-cured tobacco; contents of nicotine and total nitrogen decreased with the rising of altitude, conversely, total sugar and reducing sugar contents increased with the rising trend of altitude, and the differences on the contents of potassium （K） and chlorine（CI）, and the ratio of K to CI in different altitudes were not significant, at the altitude of 1 250-1 450 m, each chemical component indicator was better. The correlation between main meteorological factors and conventional chemical components of tobacco leaves was as follows： contents of reducing sugar and total sugar increased with the increase of rainfall and relative humidity, and decreased with the increase of sunshine duration; nicotine content increased with the increase of accumulated temperature and sunshine duration; total nitrogen （N） content increased with the increase of daily mean temperature and accumulated temperature; sugar-alkali ratio increased with the increase of rainfall. Path analysis showed that the direct effect of sunshine duration on reducing sugar and total sugar of tobacco leaves was faint, but the indirect effect was obvious; meanwhile, the direct and indirect effects of it on nicotine and total N were the greatest.
基金Supported by Youth Foundation of Hunan Institution of Humanities,Science and Technology(2009QN08)Educational Reform Project of Hunan Institution of Humanities,Science and Technology(RKJGZ1013)~~
文摘Pseudogene and fibrin peptide which has rapid evolve speed and good stability are used in this study to determine the divergence date among groups.Through calculating the evolutionary rate of hemoglobin α chain,γ chain in vertebrate（including birds and mammals）,it is concluded that the evolutionary rate of hemoglobin α chain,γ chain is not invariable.It shows different evolutionary rates in different periods,that is,faster in early evolution stage and relatively slow in later stage.
基金This work was supported by the National Natural Sciences Foundation of China (No. 30470930)the Ministry of Education of China (No. 104130)the National Program for Basic Research and Development (973) of China (No. 2004CB117304).
文摘Actin depolymerizing factor （ADF）, highly conserved in all eukaryotic cells, is a low molecular mass of actin-binding protein, which plays a key role in modulating the polymerizing and depolymerizing of the actin filaments. Four cDNAs （designated GhADF2, GhADF3, GhADF4, and GhADF5, respectively） encoding ADF proteins were isolated from cotton （Gossypium hirsutum） fiber cDNA library. GhADF2 cDNA is 705 bp in length and deduces a protein with 139 amino acids. GhADF3 cDNA is 819 bp in length and encodes a protein of 139 amino acids. GhADF4 cDNA is 804 bp in length and deduces a protein with 143 amino acids. GhADF5 cDNA is 644 bp in length and encodes a protein of 141 amino acids. The molecular evolutionary relationship of these genes was analyzed by means of bioinformatics. GhADF2 is closely related to GhADF3 （99% identity） and PetADF2 （89% identity）. GhADF4 is closely related to AtADF6 （78% identity）, and GhADF5 is closely related to AtADF5 （83% identity）. These results demonstrated that the plant ADF genes are highly conserved in structure. RT-PCR analysis showed that GhADF2 is predominantly expressed in fiber, whereas, GhADF5 is mainly expressed in cotyledons. On the other hand, it seems that GhADF3 and GhADF4 have no tissue specificity. Expression levels of different ADF genes may vary considerably in the same cell type, suggesting that they might be involved in regulating tissue development of cotton and the each ADF isoform may diverge to form the functional difference from the other ADFs during evolution.
