The nudeotide sequence of the nifLA promoter of Enterobacter cloacae E26 was determined, and the transcription start site of nifLA was mapped by the primer extension. Studies on the oxygen regulation of E. cloacae nif...The nudeotide sequence of the nifLA promoter of Enterobacter cloacae E26 was determined, and the transcription start site of nifLA was mapped by the primer extension. Studies on the oxygen regulation of E. cloacae nifLA promoter with the nifL’-lacZ fusion showed that the nifLA promoter was sensitive to oxygen as Kebsiella pneumoniae nifLA promoter reported previously. Comparison between the nifLA promoter sequences of E. cloacae and K. pneumoniae revealed the presence of an 11-bp conserved sequence between the - 24/ -12 consensus of σ54-dependent promoter and NtrC binding motif. The 11-bp sequence is speculated to be involved in the oxygen regulation of the nifLA promoter of both enteric bacteria.展开更多
Four calcium channel blockers, i.e. nifedipine, verapamil, cinnarizine and tetrandrine are currently available and used widely in treating cardiovascular diseases. To confirm the effects, if any, of calcium channel bl...Four calcium channel blockers, i.e. nifedipine, verapamil, cinnarizine and tetrandrine are currently available and used widely in treating cardiovascular diseases. To confirm the effects, if any, of calcium channel blockers on cirrhotic patients with portal hypertension, a study was performed on esophageal variceal pressure and rebleeding rate of esophageal varices after 2 years by using calcium channel blocker in 321 patients from some 23 hospitals. The results demonstrated that the calcium channel blockers could significantly reduce the esophageal variceal pressure and the portal blood flow in cirrhotic patients with portal hypertension. The proportion of patients with no recurrent gastrointestinal bleeding after 2 years medication of tetrandrine was 87.9% in tetrandrine group, significantly higher than those in the other 4 groups (P<0.05). It is suggested that tetrandrine should be more effective for cirrhotic patients with portal hypertension in preventing recurrent variceal bleeding.展开更多
In enteric bacteria, in response to the PTS system, the cAMP receptor protein (CRP) mediates the glucose effect, via regulating σ70-dependent catabolic genes at transcriptional level. In this study, it is observed th...In enteric bacteria, in response to the PTS system, the cAMP receptor protein (CRP) mediates the glucose effect, via regulating σ70-dependent catabolic genes at transcriptional level. In this study, it is observed that the nitrogen fixation capacity of Klebsiella pneumoniae varies strongly when cells are grown on different carbohydrates, and this carbon effect occurs at the level of nif gene expression. Here we show that CRP can repress σ54-dependent nif promoters (nifB, nifE, nifF, nifH, nifJ, nifLA and nifU), in a cAMP dependent fashion, in closed related E. coll background. Sequence analysis of these nif promoters indicates that there is no direct correlation between the fold of CRP-cAMP-mediated inhibition and the upstream cis elements at the promoters. In addition, the crp gene of K. pneumoniae has been isolated and sequenced, which is structural and functional highly homologous to that of E. coli. This suggests that CRP-cAMP-mediated inhibition on the nif promoters could be the reason for展开更多
This study aimed to increase bacterial growth and 5-aminolevulinic acid（ALA） biosynthesis of Rhodobacter sphaeroides in wastewater treatment through adding ferrous ion（ Fe2＋ ）. Results demonstrated that Fe2＋ eff...This study aimed to increase bacterial growth and 5-aminolevulinic acid（ALA） biosynthesis of Rhodobacter sphaeroides in wastewater treatment through adding ferrous ion（ Fe2＋ ）. Results demonstrated that Fe2＋ effectively enhanced the biomass production and ALA yield of R. sphaeroides. Moreover, the optimal Fe2＋ dosage was found to be 400 μmol/L, which was associated with the highest biomass of 4015.3 mg/L and maximum ALA yield of 15.9 mg/g-dry cell weight（mg/g-DCW）. Mechanism analysis revealed that Fe2＋ vastly improved Adenosine Triphosphate（ATP） production by up-regulating the nif gene expression, and increasing ATP enhanced the biomass and ALA yield by supplying energy for bacterial growth and ALA biosynthesis, respectively. Correlation analysis showed that the ALA and ATP yields had positive relation with nifA and nifU gene expression. In addition, the nifA and nifU gene expression displayed high consistency of co-transcription at the optimal Fe2＋ dosage.展开更多
We have developed a new 3D multi-physics multi-material code, ALE-AMR, which combines Arbitrary Lagrangian Eulerian （ALE） hydrodynamics with Adaptive Mesh Refinement （AMR） to connect the continuum to the microstru...We have developed a new 3D multi-physics multi-material code, ALE-AMR, which combines Arbitrary Lagrangian Eulerian （ALE） hydrodynamics with Adaptive Mesh Refinement （AMR） to connect the continuum to the microstructural regimes. The code is unique in its ability to model hot radiating plasmas and cold fragmenting solids. New numerical techniques were developed for many of the physics packages to work efficiently on a dynamically moving and adapting mesh. We use interface reconstruction based on volume fractions of the material components within mixed zones and reconstruct interfaces as needed. This interface reconstruction model is also used for void coalescence and fragmentation. A flexible strength/failure framework allows for pluggable material models, which may require material history arrays to determine the level of accumulated damage or the evolving yield stress in J2 plasticity models. For some applications laser rays are propagating through a virtual composite mesh consisting of the finest resolution representation of the modeled space. A new 2nd order accurate diffusion solver has been implemented for the thermal conduction and radiation transport packages. One application area is the modeling of laser/target effects including debris/shrapnel generation. Other application areas include warm dense matter, EUV lithography, and material wall interactions for fusion devices.展开更多
基金Project supported by the National Natural Science Foundation of China.
文摘The nudeotide sequence of the nifLA promoter of Enterobacter cloacae E26 was determined, and the transcription start site of nifLA was mapped by the primer extension. Studies on the oxygen regulation of E. cloacae nifLA promoter with the nifL’-lacZ fusion showed that the nifLA promoter was sensitive to oxygen as Kebsiella pneumoniae nifLA promoter reported previously. Comparison between the nifLA promoter sequences of E. cloacae and K. pneumoniae revealed the presence of an 11-bp conserved sequence between the - 24/ -12 consensus of σ54-dependent promoter and NtrC binding motif. The 11-bp sequence is speculated to be involved in the oxygen regulation of the nifLA promoter of both enteric bacteria.
文摘Four calcium channel blockers, i.e. nifedipine, verapamil, cinnarizine and tetrandrine are currently available and used widely in treating cardiovascular diseases. To confirm the effects, if any, of calcium channel blockers on cirrhotic patients with portal hypertension, a study was performed on esophageal variceal pressure and rebleeding rate of esophageal varices after 2 years by using calcium channel blocker in 321 patients from some 23 hospitals. The results demonstrated that the calcium channel blockers could significantly reduce the esophageal variceal pressure and the portal blood flow in cirrhotic patients with portal hypertension. The proportion of patients with no recurrent gastrointestinal bleeding after 2 years medication of tetrandrine was 87.9% in tetrandrine group, significantly higher than those in the other 4 groups (P<0.05). It is suggested that tetrandrine should be more effective for cirrhotic patients with portal hypertension in preventing recurrent variceal bleeding.
基金This work was supported in part by the NationalNatural Science Foundation of China (Grant No. 39925017)the State "863" Program (Grant No. 2001AA214021)the "973" Program (Grant No. 2001CB108900) from the Ministry of Science and Technology of China.
文摘In enteric bacteria, in response to the PTS system, the cAMP receptor protein (CRP) mediates the glucose effect, via regulating σ70-dependent catabolic genes at transcriptional level. In this study, it is observed that the nitrogen fixation capacity of Klebsiella pneumoniae varies strongly when cells are grown on different carbohydrates, and this carbon effect occurs at the level of nif gene expression. Here we show that CRP can repress σ54-dependent nif promoters (nifB, nifE, nifF, nifH, nifJ, nifLA and nifU), in a cAMP dependent fashion, in closed related E. coll background. Sequence analysis of these nif promoters indicates that there is no direct correlation between the fold of CRP-cAMP-mediated inhibition and the upstream cis elements at the promoters. In addition, the crp gene of K. pneumoniae has been isolated and sequenced, which is structural and functional highly homologous to that of E. coli. This suggests that CRP-cAMP-mediated inhibition on the nif promoters could be the reason for
基金supported by the National Natural Science Foundation of China(No.51708214)the High-level Personnel Research Startup Project of North China University of Water Resources and Electric Power(No.40550)the Treatment Technology Integration and Demonstration for Domestic Sewage of Typical Villages and Towns in Henan Province(No.161100310700)
文摘This study aimed to increase bacterial growth and 5-aminolevulinic acid（ALA） biosynthesis of Rhodobacter sphaeroides in wastewater treatment through adding ferrous ion（ Fe2＋ ）. Results demonstrated that Fe2＋ effectively enhanced the biomass production and ALA yield of R. sphaeroides. Moreover, the optimal Fe2＋ dosage was found to be 400 μmol/L, which was associated with the highest biomass of 4015.3 mg/L and maximum ALA yield of 15.9 mg/g-dry cell weight（mg/g-DCW）. Mechanism analysis revealed that Fe2＋ vastly improved Adenosine Triphosphate（ATP） production by up-regulating the nif gene expression, and increasing ATP enhanced the biomass and ALA yield by supplying energy for bacterial growth and ALA biosynthesis, respectively. Correlation analysis showed that the ALA and ATP yields had positive relation with nifA and nifU gene expression. In addition, the nifA and nifU gene expression displayed high consistency of co-transcription at the optimal Fe2＋ dosage.
基金the National Energy Research Scientific Computing Center,a DOE Office of Science User Facility supported by the Office of Science,U. S.Department of Energy under Contract No.DEAC02-05CH11231LBNL under DE-AC0205CH11231 was supported by the Director,Office of Science of the U.S.Department of Energy and the Petascale Initiative in Computational Science and Engineering+1 种基金LLNL was performed under the auspices of the U.S.Department of Energy by Lawrence Livermore National Security,LLC,Lawrence Livermore National Laboratory under Contract DE-AC5207NA27344UCLA and LLNL acknowledge UC Lab Fees Research Grant 09-LR-04-116741-BERA
文摘We have developed a new 3D multi-physics multi-material code, ALE-AMR, which combines Arbitrary Lagrangian Eulerian （ALE） hydrodynamics with Adaptive Mesh Refinement （AMR） to connect the continuum to the microstructural regimes. The code is unique in its ability to model hot radiating plasmas and cold fragmenting solids. New numerical techniques were developed for many of the physics packages to work efficiently on a dynamically moving and adapting mesh. We use interface reconstruction based on volume fractions of the material components within mixed zones and reconstruct interfaces as needed. This interface reconstruction model is also used for void coalescence and fragmentation. A flexible strength/failure framework allows for pluggable material models, which may require material history arrays to determine the level of accumulated damage or the evolving yield stress in J2 plasticity models. For some applications laser rays are propagating through a virtual composite mesh consisting of the finest resolution representation of the modeled space. A new 2nd order accurate diffusion solver has been implemented for the thermal conduction and radiation transport packages. One application area is the modeling of laser/target effects including debris/shrapnel generation. Other application areas include warm dense matter, EUV lithography, and material wall interactions for fusion devices.
