Improved synthesis and structure identification of L-histidine norcantharimide , a potent PP2A inhibitor was reported. Condensation between norcantharidin and L-histidine in 95% EtOH at reflux temperature affords L-hi...Improved synthesis and structure identification of L-histidine norcantharimide , a potent PP2A inhibitor was reported. Condensation between norcantharidin and L-histidine in 95% EtOH at reflux temperature affords L-histidine norcantharimide in 97.0f% yield which is much higher compared with literature, and more importantly, the configuration is retained. The chemical structure of the compound was re-elucidated through IR, FAB-MS, ^1H NMR, ^13C NMR and 2D NMR （^1H, ^13C-COSY and HMBC）, the fundamental physical data, including optical data being also firstly reported. Preliminary cytotoxicity evaluation showed that the target compound was probably more potent than norcantharidin against a panel of human cancer cell lines. Design and synthesis of amino acid （nor） cantharirnides would provide a convenient and rational structure modification of （nor） cantharidin and open new avenues to explore new promising candidates.展开更多
Adsorption properties of L-histidine on active carbon were studied in the paper, which are affected by the main parameters, such as the quantity percent of active carbon, pH value of the solution, the thne of adsorpti...Adsorption properties of L-histidine on active carbon were studied in the paper, which are affected by the main parameters, such as the quantity percent of active carbon, pH value of the solution, the thne of adsorption equilibrium and adsorption temperature. The results indicate that adsorption equilibrium time of L-his on active carbon is about 80 minutes. With tire increasing of the quantity percent of active carbon, the adsorbance of L-his decreases sharply, and increases lighter after that. When the quantity percent of active carbon is 10%, the adsorbance reaches the minimum. pH value of solution and extraction temperature have great affection on the adsorption. When the pH value is higher or lower than the pl of L-his, the adsorbance is small, even zero. It is proven that the experimental equilibrium data which are obtained under the conditions of 80 ℃ and pH=1.0, are fitted with the Freundlich equation： q=2.5914c^0.8097. Tire results can provide certain references in L-his adsorption process of industrial operation.展开更多
Objective： Based on a partialsubtilisin-like protease, Prl genomic sequence ofPythium guiyangense which has been cloned before, Panhandle PCR strategy was used to amplify the upstream flanking sequence adjacent to th...Objective： Based on a partialsubtilisin-like protease, Prl genomic sequence ofPythium guiyangense which has been cloned before, Panhandle PCR strategy was used to amplify the upstream flanking sequence adjacent to the known sequence of the Prl gene. Methods： The genomic DNA was firstly digested with BamH I and then treated with calf intestinal alkaline phosphatase（CIAP）. Next, a 5＇ phosphorylated oligonucleotide was ligated to the 5＇ ends of BamH I -digested DNA. After denaturation, intmstrand annealing and polymemse extension, a pan with a handle was formed,and lastly the nested PCR was performed. Results： A 864 bp product was amplified,which was adjacent to the known sequence of Prl gene.The gene has been accessed by GenBank （Accession：JQ975036）. Conclusion： Panhandle PCR is a quick and convenient approach for amplifying and identifying unknown partner genes,which facilitates cloning full-length Prl gene展开更多
Engineered Corynebacterium glutamicum was constructed for L-ornithine production by disrupting genes of argF and proB to prevent the flux away from L-ornithine.Effect of the inactivation of 2-oxoglutarate de-hydrogena...Engineered Corynebacterium glutamicum was constructed for L-ornithine production by disrupting genes of argF and proB to prevent the flux away from L-ornithine.Effect of the inactivation of 2-oxoglutarate de-hydrogenase complex(ODHC) on L-ornithine production was also investigated.It was found that the inactivation of ODHC by knockout of the kgd gene enhanced L-ornithine production.The engineered C.glutamicum ATCC13032(ΔargFΔproBΔkgd) produced L-ornithine up to 4.78 g·L-1 from 0.24 g·L-1 of the wild-type strain.In order to understand the mechanism of L-ornithine production in C.glutamicum ATCC13032(ΔargFΔproBΔkgd) and find out new strategies for further enhancing L-ornithine production,the comparative proteome between the wild-type and the engineered strain was analyzed.L-Ornithine overproduction in the engineered strain was related to the up-regulation of the expression levels of enzymes involved in L-ornithine biosynthesis pathway and down-regulation of the expression levels of proteins involved in pentose phosphate pathway.The overexpression of genes in the upstream pathway of glutamate to increase the availability of endogenous glutamate may further in-crease ornithine production in the engineered C.glutamicum and the ornithine synthesis enzymes(ArgCJBD) may not be the limiting enzymes in the engineered C.glutamicum.展开更多
In this paper, the global existence of weak s olutions to the initial boundary value problem for Boltzmann-Poisson system is proved. The proof is based on the regularization and the stability of the veloci ty averages...In this paper, the global existence of weak s olutions to the initial boundary value problem for Boltzmann-Poisson system is proved. The proof is based on the regularization and the stability of the veloci ty averages and the compactness results on L 1-theory.展开更多
AIM: To examine the effectiveness of human placental inhibitors, by injecting vitamin E to rats with transplanted Morris-5123 hepatoma, on the expression of cathepsins B and L in tumor, liver, lung and blood sera afte...AIM: To examine the effectiveness of human placental inhibitors, by injecting vitamin E to rats with transplanted Morris-5123 hepatoma, on the expression of cathepsins B and L in tumor, liver, lung and blood sera after transplantation of Morris 5123 hepatoma. METHODS: Animals were divided into 10 groups receiving three different concentrations of vitamin E and inhibitors along or in combination and compared with negative control (healthy rats) and positive control (tumor rats). Effectiveness of treatment was evaluated with regard to survival time, tumor response and determination of the activities of proteolytic enzymes and their inhibitors using flurogenic substrates. RESULTS: Cathepsins B and L activities were elevated by 16-fold in comparison with negative control tissues, and their endogenous inhibitor activity decreased by 1.2-fold before treatment. In several cases, tumors completely disappeared following vitamin E plus human placental cyteine protease inhibitor (CPI) compared with controls. The number of complete tumor responses was higher when 20 m/kg vitamin E plus 400 μg of CPI was used, i.e. 7/10 rats survived more than two mo. Cathepsins B and L were expressed significantly in tumor, liver, lung tissues and sera in parallel to the increasing of the endogenous inhibitor activity compared with the controls after treatment(P<0.0001) CONCLUSION: The data indicate formation of metastasis significantly reduced in treated rats, which might provide a therapeutic basis for anti-cancer therapy.展开更多
Let MPT ( v,λ ) denote a maximum packing of triples of order v with index λ and TS ( u,λ ) denote a triple system of order u with index λ . In this paper, for v ≥6, we determine necessary and sufficient condition...Let MPT ( v,λ ) denote a maximum packing of triples of order v with index λ and TS ( u,λ ) denote a triple system of order u with index λ . In this paper, for v ≥6, we determine necessary and sufficient conditions for enclosing an MPT ( v,λ ) in a TS ( v+1,λ+m ) with one extra point and minimal increase in λ .展开更多
AtCRE1 is known to be a cytokinin receptor in Arabidopsis. The AtCRE1 protein contains CHASE domain at the N-terminal part, followed by a transmitter (histidine kinase) domain and two receiver domains. The N-terminal...AtCRE1 is known to be a cytokinin receptor in Arabidopsis. The AtCRE1 protein contains CHASE domain at the N-terminal part, followed by a transmitter (histidine kinase) domain and two receiver domains. The N-terminal CHASE domain of AtCRE1 contains putative recognition sites for cytokinin. Five CHASE domains containing proteins were found in rice, OsCRL1a, OsCRL1b, OsCRL2, OsCRL3, and OsCRL4. OsCRL1a, OsCRL1b, OsCRL2 and OsCRL3 contain the four domains existing in CRE1, whereas OsCRL4 only contains the CHASE domain and a putative Ser/Thr protein kinase domain. The authors cloned the encoding gene OsCRL4 and found that it represents a new member of the cytokinin receptor protein in rice.展开更多
By employing three typical equations of states （EOSs） of the crust matter, the effect of the crust on the structure and properties are investigated, where the core matter is described by the MDIxl model and the non-...By employing three typical equations of states （EOSs） of the crust matter, the effect of the crust on the structure and properties are investigated, where the core matter is described by the MDIxl model and the non-Newtonian gravity （described by the Yukawa contribution） is considered. It is shown that the EOSs of the crust matter have a notable effect on the mass-radius relation and the moment of inertia.展开更多
According to a program of Braverman, Kazhdan and NgS, for a large class of split unramified reductive groups G and representations p of the dual group G, the unramified local L-factor L（s, π, ρ） can be expressed a...According to a program of Braverman, Kazhdan and NgS, for a large class of split unramified reductive groups G and representations p of the dual group G, the unramified local L-factor L（s, π, ρ） can be expressed as the trace of π（fρ,s） for a function fρ,s with non-compact support whenever Re（s） ≥ 0. Such a function should have useful interpretations in terms of geometry or eombinatories, and it can be plugged into the trace formula to study certain sums of automorphic L-functions. It also fits into the conjectural framework of Schwartz spaces for reductive monoids due to Sakellaridis, who coined the term basic functions; this is supposed to lead to a generalized Tamagawa-Godement-Jaequet theory for （G, ρ）. In this paper, we derive some basic properties for the basic functions fρ,s and interpret them via invariant theory. In particular, their coefficients are interpreted as certain generalized Kostka-Foulkes polynomials defined by Panyushev. These coefficients can be encoded into a rational generating function.展开更多
We obtain an equation among invariants obtained from the Alexander module of an amphicheiral link. For special cases, it deduces necessary conditions on the Alexander polynomial. By using the present results and some ...We obtain an equation among invariants obtained from the Alexander module of an amphicheiral link. For special cases, it deduces necessary conditions on the Alexander polynomial. By using the present results and some known results, we show that the Alexander polynomial of an algebraically split component- preservingly （±）-amphicheiral link with even components is zero, and we determine prime amphieheiral links with at least 2 components and up to 9 crossings.展开更多
基金Science and Technology Program of Guangdong Province(Grant No.2006B35604002)Guangzhou City(Grant No.2007JI-C0261).
文摘Improved synthesis and structure identification of L-histidine norcantharimide , a potent PP2A inhibitor was reported. Condensation between norcantharidin and L-histidine in 95% EtOH at reflux temperature affords L-histidine norcantharimide in 97.0f% yield which is much higher compared with literature, and more importantly, the configuration is retained. The chemical structure of the compound was re-elucidated through IR, FAB-MS, ^1H NMR, ^13C NMR and 2D NMR （^1H, ^13C-COSY and HMBC）, the fundamental physical data, including optical data being also firstly reported. Preliminary cytotoxicity evaluation showed that the target compound was probably more potent than norcantharidin against a panel of human cancer cell lines. Design and synthesis of amino acid （nor） cantharirnides would provide a convenient and rational structure modification of （nor） cantharidin and open new avenues to explore new promising candidates.
基金The Special Fund of the Education Committee of Fujian Province (No. 2004HO13 ) The Special Fund of the Education Committee of Quanzhou (No. 2005G6) and Subproject (No. 2005ZD4-5)
文摘Adsorption properties of L-histidine on active carbon were studied in the paper, which are affected by the main parameters, such as the quantity percent of active carbon, pH value of the solution, the thne of adsorption equilibrium and adsorption temperature. The results indicate that adsorption equilibrium time of L-his on active carbon is about 80 minutes. With tire increasing of the quantity percent of active carbon, the adsorbance of L-his decreases sharply, and increases lighter after that. When the quantity percent of active carbon is 10%, the adsorbance reaches the minimum. pH value of solution and extraction temperature have great affection on the adsorption. When the pH value is higher or lower than the pl of L-his, the adsorbance is small, even zero. It is proven that the experimental equilibrium data which are obtained under the conditions of 80 ℃ and pH=1.0, are fitted with the Freundlich equation： q=2.5914c^0.8097. Tire results can provide certain references in L-his adsorption process of industrial operation.
基金Supported by the Guangxi Department of education scientific research funds,China(No.200103YB154)
文摘Objective： Based on a partialsubtilisin-like protease, Prl genomic sequence ofPythium guiyangense which has been cloned before, Panhandle PCR strategy was used to amplify the upstream flanking sequence adjacent to the known sequence of the Prl gene. Methods： The genomic DNA was firstly digested with BamH I and then treated with calf intestinal alkaline phosphatase（CIAP）. Next, a 5＇ phosphorylated oligonucleotide was ligated to the 5＇ ends of BamH I -digested DNA. After denaturation, intmstrand annealing and polymemse extension, a pan with a handle was formed,and lastly the nested PCR was performed. Results： A 864 bp product was amplified,which was adjacent to the known sequence of Prl gene.The gene has been accessed by GenBank （Accession：JQ975036）. Conclusion： Panhandle PCR is a quick and convenient approach for amplifying and identifying unknown partner genes,which facilitates cloning full-length Prl gene
基金Supported by the National Natural Science Foundation of China (30970089,20876181,20831006)the Natural Science Foundation of Guangdong Province (9351027501000003)
文摘Engineered Corynebacterium glutamicum was constructed for L-ornithine production by disrupting genes of argF and proB to prevent the flux away from L-ornithine.Effect of the inactivation of 2-oxoglutarate de-hydrogenase complex(ODHC) on L-ornithine production was also investigated.It was found that the inactivation of ODHC by knockout of the kgd gene enhanced L-ornithine production.The engineered C.glutamicum ATCC13032(ΔargFΔproBΔkgd) produced L-ornithine up to 4.78 g·L-1 from 0.24 g·L-1 of the wild-type strain.In order to understand the mechanism of L-ornithine production in C.glutamicum ATCC13032(ΔargFΔproBΔkgd) and find out new strategies for further enhancing L-ornithine production,the comparative proteome between the wild-type and the engineered strain was analyzed.L-Ornithine overproduction in the engineered strain was related to the up-regulation of the expression levels of enzymes involved in L-ornithine biosynthesis pathway and down-regulation of the expression levels of proteins involved in pentose phosphate pathway.The overexpression of genes in the upstream pathway of glutamate to increase the availability of endogenous glutamate may further in-crease ornithine production in the engineered C.glutamicum and the ornithine synthesis enzymes(ArgCJBD) may not be the limiting enzymes in the engineered C.glutamicum.
文摘In this paper, the global existence of weak s olutions to the initial boundary value problem for Boltzmann-Poisson system is proved. The proof is based on the regularization and the stability of the veloci ty averages and the compactness results on L 1-theory.
文摘AIM: To examine the effectiveness of human placental inhibitors, by injecting vitamin E to rats with transplanted Morris-5123 hepatoma, on the expression of cathepsins B and L in tumor, liver, lung and blood sera after transplantation of Morris 5123 hepatoma. METHODS: Animals were divided into 10 groups receiving three different concentrations of vitamin E and inhibitors along or in combination and compared with negative control (healthy rats) and positive control (tumor rats). Effectiveness of treatment was evaluated with regard to survival time, tumor response and determination of the activities of proteolytic enzymes and their inhibitors using flurogenic substrates. RESULTS: Cathepsins B and L activities were elevated by 16-fold in comparison with negative control tissues, and their endogenous inhibitor activity decreased by 1.2-fold before treatment. In several cases, tumors completely disappeared following vitamin E plus human placental cyteine protease inhibitor (CPI) compared with controls. The number of complete tumor responses was higher when 20 m/kg vitamin E plus 400 μg of CPI was used, i.e. 7/10 rats survived more than two mo. Cathepsins B and L were expressed significantly in tumor, liver, lung tissues and sera in parallel to the increasing of the endogenous inhibitor activity compared with the controls after treatment(P<0.0001) CONCLUSION: The data indicate formation of metastasis significantly reduced in treated rats, which might provide a therapeutic basis for anti-cancer therapy.
文摘Let MPT ( v,λ ) denote a maximum packing of triples of order v with index λ and TS ( u,λ ) denote a triple system of order u with index λ . In this paper, for v ≥6, we determine necessary and sufficient conditions for enclosing an MPT ( v,λ ) in a TS ( v+1,λ+m ) with one extra point and minimal increase in λ .
基金Project supported by the National Natural Science Foundation of China
文摘AtCRE1 is known to be a cytokinin receptor in Arabidopsis. The AtCRE1 protein contains CHASE domain at the N-terminal part, followed by a transmitter (histidine kinase) domain and two receiver domains. The N-terminal CHASE domain of AtCRE1 contains putative recognition sites for cytokinin. Five CHASE domains containing proteins were found in rice, OsCRL1a, OsCRL1b, OsCRL2, OsCRL3, and OsCRL4. OsCRL1a, OsCRL1b, OsCRL2 and OsCRL3 contain the four domains existing in CRE1, whereas OsCRL4 only contains the CHASE domain and a putative Ser/Thr protein kinase domain. The authors cloned the encoding gene OsCRL4 and found that it represents a new member of the cytokinin receptor protein in rice.
基金Supported by the National Natural Science Foundation of China under Grant No.10947023the Fundamental Research Funds for the Central Universities under Grant No.2009ZM0193the SRP of SCUT under Grant No.D210632w
文摘By employing three typical equations of states （EOSs） of the crust matter, the effect of the crust on the structure and properties are investigated, where the core matter is described by the MDIxl model and the non-Newtonian gravity （described by the Yukawa contribution） is considered. It is shown that the EOSs of the crust matter have a notable effect on the mass-radius relation and the moment of inertia.
文摘According to a program of Braverman, Kazhdan and NgS, for a large class of split unramified reductive groups G and representations p of the dual group G, the unramified local L-factor L（s, π, ρ） can be expressed as the trace of π（fρ,s） for a function fρ,s with non-compact support whenever Re（s） ≥ 0. Such a function should have useful interpretations in terms of geometry or eombinatories, and it can be plugged into the trace formula to study certain sums of automorphic L-functions. It also fits into the conjectural framework of Schwartz spaces for reductive monoids due to Sakellaridis, who coined the term basic functions; this is supposed to lead to a generalized Tamagawa-Godement-Jaequet theory for （G, ρ）. In this paper, we derive some basic properties for the basic functions fρ,s and interpret them via invariant theory. In particular, their coefficients are interpreted as certain generalized Kostka-Foulkes polynomials defined by Panyushev. These coefficients can be encoded into a rational generating function.
基金supported by National Natural Science Foundation of China (Grant No. 10801021/a010402)
文摘We obtain an equation among invariants obtained from the Alexander module of an amphicheiral link. For special cases, it deduces necessary conditions on the Alexander polynomial. By using the present results and some known results, we show that the Alexander polynomial of an algebraically split component- preservingly （±）-amphicheiral link with even components is zero, and we determine prime amphieheiral links with at least 2 components and up to 9 crossings.
