In this study,circular dichroism(CD)and molecular dynamics(MD)simulation were used to investigate the thermal unfolding pathway of staphylococcal enterotoxin B(SEB)at temperatures of 298–371 and 298–500 K,and the re...In this study,circular dichroism(CD)and molecular dynamics(MD)simulation were used to investigate the thermal unfolding pathway of staphylococcal enterotoxin B(SEB)at temperatures of 298–371 and 298–500 K,and the relationship between the experimental and simulation results were explored.Our computational findings on the secondary structure of SEB showed that at room temperature,the CD spectroscopic results were highly consistent with the MD results.Moreover,under heating conditions,the changing trends of helix,sheet and random coil obtained by CD spectral fitting were highly consistent with those obtained by MD.In order to gain a deeper understanding of the thermal stability mechanism of SEB,the MD trajectories were analyzed in terms of root mean square deviation(RMSD),secondary structure assignment(SSA),radius of gyration(R_(g)),free energy surfaces(FES),solvent-accessible surface area(SASA),hydrogen bonds and salt bridges.The results showed that at low heating temperature,domain Ⅰ without loops(omitting the mobile loop region)mainly relied on hydrophobic interaction to maintain its thermal stability,whereas the thermal stability of domain Ⅱ was mainly controlled by salt bridges and hydrogen bonds.Under high heating temperature conditions,the hydrophobic interactions in domain Ⅰ without loops were destroyed and the secondary structure was almost completely lost,while domain Ⅱ could still rely on salt bridges as molecular staples to barely maintain the stability of the secondary structure.These results help us to understand the thermodynamic and kinetic mechanisms that maintain the thermal stability of SEB at the molecular level,and provide a direction for establishing safer and more effective food sterilization processes.展开更多
The use of the RAPD technique was investigated on a set of 73 genotypes of 18 wild grape species native to China, and one interspecific hybrid, seven Vitis vinifera L. cultivars, one rootstock cultivar and one str...The use of the RAPD technique was investigated on a set of 73 genotypes of 18 wild grape species native to China, and one interspecific hybrid, seven Vitis vinifera L. cultivars, one rootstock cultivar and one strain of V. riparia L. Genetic diversity among these grapes was investigated based on RAPD analysis. The screening of 280 decamer oligonucleotides allowed the selection of 20 primers used for the analysis. A total of 191 RAPD markers were produced from the 20 selected primers. Relationships among the 83 clones or accessions based on their genetic distances were clustered using unweighted pair_group method arithmetic average (UPGMA) analysis in a dendrogram. Twenty_two clusters which fortunately adapted to 22 grape species level were clearly resolved on the dendrogram. The 18 wild grape species native to China were grouped into ten subclusters. The largest distance was found between V. riparia L., V. vinifera L., interspecific hybrid ( V. vinifera L.× V. larbrusca L.) and the wild grapes native to China. Among the wild grapes native to China, the largest distance was found between V. hancockii Hance and the other wild species. V. qinlingensis P.C.He was the second. Large genetic variation occurred among the different flower_type clones in one species.展开更多
Pueraria lobata ( Wild. ) Ohwi ( Ye-Ge in Chinese ) is a perennial herb ofthe genus Pueraria, which belongs to the Leguminosae family. It is commonly employed to relievefever and dysentery, promote the production of b...Pueraria lobata ( Wild. ) Ohwi ( Ye-Ge in Chinese ) is a perennial herb ofthe genus Pueraria, which belongs to the Leguminosae family. It is commonly employed to relievefever and dysentery, promote the production of body fluid, reduce stiffness and pain of the nape,and for the treatment of cardiovascular diseases, e. g. hypertension, myocardial infarction, andarrhythmia. Previous phytochemical studies on P. lobata reported a number of bioactive isoflavones,e. g. daidzein, daidzin, and puerarin. Further investigation of its root has led to isolation offourteen compounds and their structures were identified as daidzein, ononin, daidzin, 3'' -methoxypuerarin, puerarin, pueroside B, daidzein-8-C-apiosyl- (1-6)-glucoside, 3''-hydroxy-puerarin,puerarinxyloside, daidzein-7, 4'' -O-glucoside, puerarin-4''-O-glucoside, mirificin-4''-O-glucoside,sissotorin, and pueroside C. Compounds 11 and 13 were isolated from the root of P. lobata for thefirst time.展开更多
[Objective] This study aimed to screen the effective pesticide for control-ling Parathrene regalis Butler. [Method] By field trials, the effects of six kinds of commonly used pesticides on P. regalis were determined. ...[Objective] This study aimed to screen the effective pesticide for control-ling Parathrene regalis Butler. [Method] By field trials, the effects of six kinds of commonly used pesticides on P. regalis were determined. ln addition, different agri-cultural measures were employed to integrate control technologies. [Result] At the early occurrence stage of P. regalis, spraying 7.5g/hm2 5% emamectin benzoate EC, 13.5 g/hm2 2% avermectin EC and 25 g/hm2 2.5% lambda-cyhalothrin EC can ef-fectively control P. regalis. [Conclusion] This study provided reference for the pre-vention and control of P. regalis.展开更多
文摘In this study,circular dichroism(CD)and molecular dynamics(MD)simulation were used to investigate the thermal unfolding pathway of staphylococcal enterotoxin B(SEB)at temperatures of 298–371 and 298–500 K,and the relationship between the experimental and simulation results were explored.Our computational findings on the secondary structure of SEB showed that at room temperature,the CD spectroscopic results were highly consistent with the MD results.Moreover,under heating conditions,the changing trends of helix,sheet and random coil obtained by CD spectral fitting were highly consistent with those obtained by MD.In order to gain a deeper understanding of the thermal stability mechanism of SEB,the MD trajectories were analyzed in terms of root mean square deviation(RMSD),secondary structure assignment(SSA),radius of gyration(R_(g)),free energy surfaces(FES),solvent-accessible surface area(SASA),hydrogen bonds and salt bridges.The results showed that at low heating temperature,domain Ⅰ without loops(omitting the mobile loop region)mainly relied on hydrophobic interaction to maintain its thermal stability,whereas the thermal stability of domain Ⅱ was mainly controlled by salt bridges and hydrogen bonds.Under high heating temperature conditions,the hydrophobic interactions in domain Ⅰ without loops were destroyed and the secondary structure was almost completely lost,while domain Ⅱ could still rely on salt bridges as molecular staples to barely maintain the stability of the secondary structure.These results help us to understand the thermodynamic and kinetic mechanisms that maintain the thermal stability of SEB at the molecular level,and provide a direction for establishing safer and more effective food sterilization processes.
基金openfoundationofNationalKeyBiotechnologyLaboratoryforTropicalCropsHaikou China
文摘The use of the RAPD technique was investigated on a set of 73 genotypes of 18 wild grape species native to China, and one interspecific hybrid, seven Vitis vinifera L. cultivars, one rootstock cultivar and one strain of V. riparia L. Genetic diversity among these grapes was investigated based on RAPD analysis. The screening of 280 decamer oligonucleotides allowed the selection of 20 primers used for the analysis. A total of 191 RAPD markers were produced from the 20 selected primers. Relationships among the 83 clones or accessions based on their genetic distances were clustered using unweighted pair_group method arithmetic average (UPGMA) analysis in a dendrogram. Twenty_two clusters which fortunately adapted to 22 grape species level were clearly resolved on the dendrogram. The 18 wild grape species native to China were grouped into ten subclusters. The largest distance was found between V. riparia L., V. vinifera L., interspecific hybrid ( V. vinifera L.× V. larbrusca L.) and the wild grapes native to China. Among the wild grapes native to China, the largest distance was found between V. hancockii Hance and the other wild species. V. qinlingensis P.C.He was the second. Large genetic variation occurred among the different flower_type clones in one species.
文摘Pueraria lobata ( Wild. ) Ohwi ( Ye-Ge in Chinese ) is a perennial herb ofthe genus Pueraria, which belongs to the Leguminosae family. It is commonly employed to relievefever and dysentery, promote the production of body fluid, reduce stiffness and pain of the nape,and for the treatment of cardiovascular diseases, e. g. hypertension, myocardial infarction, andarrhythmia. Previous phytochemical studies on P. lobata reported a number of bioactive isoflavones,e. g. daidzein, daidzin, and puerarin. Further investigation of its root has led to isolation offourteen compounds and their structures were identified as daidzein, ononin, daidzin, 3'' -methoxypuerarin, puerarin, pueroside B, daidzein-8-C-apiosyl- (1-6)-glucoside, 3''-hydroxy-puerarin,puerarinxyloside, daidzein-7, 4'' -O-glucoside, puerarin-4''-O-glucoside, mirificin-4''-O-glucoside,sissotorin, and pueroside C. Compounds 11 and 13 were isolated from the root of P. lobata for thefirst time.
基金Supported by National Spark Program of China([2014]No.257)~~
文摘[Objective] This study aimed to screen the effective pesticide for control-ling Parathrene regalis Butler. [Method] By field trials, the effects of six kinds of commonly used pesticides on P. regalis were determined. ln addition, different agri-cultural measures were employed to integrate control technologies. [Result] At the early occurrence stage of P. regalis, spraying 7.5g/hm2 5% emamectin benzoate EC, 13.5 g/hm2 2% avermectin EC and 25 g/hm2 2.5% lambda-cyhalothrin EC can ef-fectively control P. regalis. [Conclusion] This study provided reference for the pre-vention and control of P. regalis.
