A novel La complex with methyl-2-pyridyl ketone benzoyl hydrazone has been synthesized and determined by single crystal X-ray diffraction. The crystal is monoclinic with space group C2/c, a =1 7081(3) nm, b =1 ...A novel La complex with methyl-2-pyridyl ketone benzoyl hydrazone has been synthesized and determined by single crystal X-ray diffraction. The crystal is monoclinic with space group C2/c, a =1 7081(3) nm, b =1 5660(3) nm, c =1 3512(3) nm, α=90 00°, β=94 39(1)°, γ=90 00°, V =3 6037(12) nm 3, Z =4 . The complex is a ten-coordinated one with a lanthanum ion surrounded by a N 4O 6 set. The crystal structure is stabilized by hydrogen bonds between water molecules and NO - 3 anions.展开更多
Synthetic phosphoethanolamine(Pho-s)is a monophosphoester ester with anti-inflammatory and pro-apoptotic properties.Meclizine chloridrate(MC)is a histamine H1 receptor blocker that is also able to inhibit cellular res...Synthetic phosphoethanolamine(Pho-s)is a monophosphoester ester with anti-inflammatory and pro-apoptotic properties.Meclizine chloridrate(MC)is a histamine H1 receptor blocker that is also able to inhibit cellular respiration.However,MC does not inhibit cellular respiration in isolated mitochondria such as antimycin and rotenone.Methyl-β-cyclodextrin(MβCD)belongs to theβ-cyclodextrin family,which is capable of removing cholesterol from the plasma membrane.The aim of this study was to evaluate the proliferative effects of meclizine chloridrate and methyl-β-cyclodextrin compounds associated with synthetic phosphoethanolamine in a triple-negative human breast tumor line,MDA-MB-231 Cell viability of the tumor line and normal cells FN1 was evaluated by MTT colorimetric test;the production of free radicals was determined by lipoperoxidation(LPO)test;and the percentage of cell cycle phases and proliferative index was evaluated by flow cytometry.Cell viability demonstrated a significant decrease with the treatments of MβCD,MC and Pho-s associated with MC.The production of free radicals decreases significantly in all treatments.In addition,a significant increase of DNA fragment and decrease in G0/G1 cell cycle phase were observed in cellular percentage with concentrations of 20 and 30 mM of Pho-s in association with MC and MβCD,respectively.展开更多
Two N-donor ligands mediated Cd(Ⅱ) coordination polymers, namely,[Cd(L)(dmpz)2]n (1) and {[Cd(L)(atr)05(H20)](H2O)}n (2) (H2L = methyl-3-hydroxy-5-carboxy-2-thiophenecarboxylate, dmpz = 3,5-dimethy...Two N-donor ligands mediated Cd(Ⅱ) coordination polymers, namely,[Cd(L)(dmpz)2]n (1) and {[Cd(L)(atr)05(H20)](H2O)}n (2) (H2L = methyl-3-hydroxy-5-carboxy-2-thiophenecarboxylate, dmpz = 3,5-dimethylpyrazole, and atr= 4-amino-l,2,4-triazole), havebeen produced. Their structures were characterized by single-crystal X-ray diffraction analysis,elemental analyses and infrared spectra. Compound 1 possesses a one-dimensional (1D) chainstructure and is finally extended into a three-dimensional (3D) supramolecular architecturethough hydrogen bonding interactions. Compound 2 features a two-dimensional (2D) networkwith 4-connected sql topology based on dinuclear Cd(Ⅱ) clusters as nodes, which is alsoassembled into a 3D supramolecular architecture through hydrogen bonding interactions.Furthermore, compounds 1 and 2 exhibit high thermal stabilities and intense fluorescent emissionin the solid, and can be explored as potential luminescent materials.展开更多
The syntheses of N-Methyl-14C benzyl amine and N-Methyl-14C benzyl nitrosamine are reported. Specific activities were approximately 920 MBq/mmol. Chemical and radiochemical purity checked by HPLC were more than 95%.
An improved method for preparation of 4-methyl-2-phenyl piperazine and its derivatives with higher yield and inexpensive reagents was developed, the products were characterized by 1H-NMR and MS.
The title complex, Cl3SnCH2CH(CH3)CO2CH3L (1), was synthesized by the reaction of methyl 2-methyl-3-trichlorostannylpropionate with benzylmethylsulfoxide (L) in solid state at room temperature and readily underwent tr...The title complex, Cl3SnCH2CH(CH3)CO2CH3L (1), was synthesized by the reaction of methyl 2-methyl-3-trichlorostannylpropionate with benzylmethylsulfoxide (L) in solid state at room temperature and readily underwent transesterification into the corresponding analogues Cl3SnCH2CH(CH3)CO2RL when reacted with an alcohol ROH. The structural features of these compounds were described, and the possible mechanism of transesterification was suggested.展开更多
A zinc(Ⅱ) compound [ZnCl2(mpcm)2](1,mpcm = methyl-3-pyridylcarbamate) was prepared by solvothermal reaction and characterized by elemental analysis,IR spectroscopy,TGA and single-crystal X-ray diffraction.The c...A zinc(Ⅱ) compound [ZnCl2(mpcm)2](1,mpcm = methyl-3-pyridylcarbamate) was prepared by solvothermal reaction and characterized by elemental analysis,IR spectroscopy,TGA and single-crystal X-ray diffraction.The crystal is of monoclinic system,space group P21/n,C14H16ZnCl2N4O4,Mr = 440.58,a = 8.7893(7),b = 24.978(2),c = 9.2510(8),β = 109.318(1)°,V = 1916.6(3)3,Z = 4,θ = 1.63~25.20°,Dc = 1.527 g/cm3,μ = 1.585 mm-1,F(000) = 896,the final R = 0.0255 and wR = 0.0654 for 3080 observed reflections with Ⅰ 〉 2σ(Ⅰ).The zinc atom is four-coordinated by the pyridyl groups of two mpcm ligands and two chloride ions with a tetrahedral geometry.Two [ZnCl2(mpcm)2] subunits are held together by a pair of hydrogen bonds,forming a 32-membered macrocyclic dimer,which is further extended into a 3D tubular structure via hydrogen bonding.展开更多
Methyl-(γ-chloropropyl)dichlorosilane was synthesized under the catalysis of a silicasupported Karstedt-type catalyst. By orthogonal experimental design method, the optimum reaction parameters such as reactants rat...Methyl-(γ-chloropropyl)dichlorosilane was synthesized under the catalysis of a silicasupported Karstedt-type catalyst. By orthogonal experimental design method, the optimum reaction parameters such as reactants ratio, reaction temperature and time, and the dosage of catalyst, were determined. At the optimum reaction condition the product yield reached 78.42%, which is higher than that reported in the literatures.展开更多
A new spectrofluorimetric method for determination of trace terbium based on its reaction with 2.6-his-(1'-phenyl-3'-methyl-5'- pyridinediacyl (H_2PMBPP) and N- cetylpyridium bromide (CPB). at an apparent ...A new spectrofluorimetric method for determination of trace terbium based on its reaction with 2.6-his-(1'-phenyl-3'-methyl-5'- pyridinediacyl (H_2PMBPP) and N- cetylpyridium bromide (CPB). at an apparent pH=5.0 provided by a hexamethylenetetramine (5% w/w)-hydrochloric acid buffer,is propesed. The calibration graph is linear in the ran ge from展开更多
Nine new derivatives of 7 β - (5- methyl- 1- aryl- 1H-1, 2, 3- triazoly- 4- carboxamido) cephalosporins were synthesized by acylction of 7 β -amino group of 7-ACA, 7-ADCA and 7-ACT with 5 -methsyl- 1 -aryl- 1 H- 1,2...Nine new derivatives of 7 β - (5- methyl- 1- aryl- 1H-1, 2, 3- triazoly- 4- carboxamido) cephalosporins were synthesized by acylction of 7 β -amino group of 7-ACA, 7-ADCA and 7-ACT with 5 -methsyl- 1 -aryl- 1 H- 1,2,3-triazoly-4-formyl chloride. The structure of the compounds were confirmed by elementray analysis IR, HNMR and FAB-MS. Some of them showed significant antibacterial activity展开更多
The paper reports the synthetic procedure and character of Copper(II) binuclearcoordination compound of 1,4-bis-(1'-phenyl-3'-methyl-5'-pyrazolone Thenon-isothermal kinetics of thermal decomposition of the...The paper reports the synthetic procedure and character of Copper(II) binuclearcoordination compound of 1,4-bis-(1'-phenyl-3'-methyl-5'-pyrazolone Thenon-isothermal kinetics of thermal decomposition of the complex has been stUdied from the TG-DTGcurves by means of the Achar et al. and Coats-Redfern methods,the most probab1e kinetic equation canbe expressed as dofdtrAe -E / RT * l /(2Q).The corresponding kinetic compensation effect expressions arefound to be lnuA=0. 1794E+0. 1689.The non-isothermal thermal decomposition process of the complex isone-dimensional diffusion.But electrochemical studies of the complex(Cu2L'2)from cyclic voltamrnetriccurves by means of powder microelectrodes technique'',shows one two-electron irreversible process.展开更多
DNA methylation is a critical epigenetic mechanism that influences gene transcription, genomic stability, X-chromosome inactivation and other factors, and appropriate DNA methylation is crucial in development. DNA met...DNA methylation is a critical epigenetic mechanism that influences gene transcription, genomic stability, X-chromosome inactivation and other factors, and appropriate DNA methylation is crucial in development. DNA methyltransferase 1 (DNMT1) plays an important role in maintaining the established methylation pattern during DNA replication. Although the effect of DNA methylation on embryonic development has been well known in vertebrates, little research has been carried out in invertebrates, especially in marine bivalves. In this study, the DNMT1 gene (MyDNMT1) was firstly identified from Mizuhopecten yessoensis. The full-length cDNA of MyDNMT1 was 5 039 bp, consisted of a 5' untranslated region (5'-UTR) of 79 bp, a 3' untranslated region (3'-UTR) of 199 bp, and a 4 761 bp open reading frame (ORF) encoding a peptide of 1 586 amino acids without a putative signal peptide. The relative mRNA expression level of MyDNMT1 was measured during the embryonic development of M. ydssoensis using real-time PCR, which revealed that the level at stage zygote and trochophore were significantly higher than that at other stages. We further examined the global DNA methylation during development by colorimetric method. The results showed that the methylation level was increased and reached the peak at blastula stage, then dramatically decreased, and fluctuated at early D-shaped larva stage. This study provided greater insight into the DNA methylation of embryonic development, which obtained a better understanding of the relationship between the DNA methylation and the embryonic development in bivalve mollusks.展开更多
There are more than 250 kinds of Zanthoxylum plants in the world, of which about 40 species grow in China. In last 30 years, nearly 80 kinds of the plants have been studicd intensively and the results show that they a...There are more than 250 kinds of Zanthoxylum plants in the world, of which about 40 species grow in China. In last 30 years, nearly 80 kinds of the plants have been studicd intensively and the results show that they are of different chemical compositions and various physiological actions, such as having anthelmintic action, bacteriostasis,展开更多
One two-dimensional coordination polymer with a formula of {[Cd(L)(imidazole)(H2O)](H2O)}n(1) was obtained by the synthetic reactions in aqueous solution using a newly synthesized H2L(H2L = methyl-3-hydroxy...One two-dimensional coordination polymer with a formula of {[Cd(L)(imidazole)(H2O)](H2O)}n(1) was obtained by the synthetic reactions in aqueous solution using a newly synthesized H2L(H2L = methyl-3-hydroxy-5-carboxy-2-thiophenecarboxylate) ligand.Compound1 crystallizes in monoclinic system,space group C2/c with a = 18.3176(11),b = 8.5366(9),c =8.4152(5)A,β = 101.789(6)°,V = 2797.1(3)A^3,Dc = 1.979 g/cm^3,C(10)H(12)N2O7SCd,Mr = 416.68 F(000) = 1648,μ = 1.745 mm^-1,F(000) = 1648,the final R = 0.0323 and wR = 0.0604 for 2604 observed reflections with I 〉 2s(I).Structure analyses reveal that the compound is constructed by dinuclear Cd(Ⅱ) clusters bridged by two hydroxyl oxygens of L^2-anions,which features a two-dimensional network with 4-connected sql topology.Furthermore,the compound exhibits high thermal stability and intense fluorescent emission,and could be explored for potentia luminescent materials.展开更多
Cholesterol is biosynthesized by all animal cells. Beyond its metabolic role in steroidogenesis, it is enriched in the plasma membrane where it has key structural and regulatory functions. Cholesterol is thus presumab...Cholesterol is biosynthesized by all animal cells. Beyond its metabolic role in steroidogenesis, it is enriched in the plasma membrane where it has key structural and regulatory functions. Cholesterol is thus presumably important for post-injury axon regrowth, and this notion is supported by studies showing that impairment of local cholesterol reutilization impeded regeneration. However, several studies have also shown that statins, inhibitors of 3-hydroxy-3-methylglutaryl-Co A reductase, are enhancers of axon regeneration, presumably acting through an attenuation of the mevalonate isoprenoid pathway and consequent reduction in protein prenylation. Several recent reports have now shown that cholesterol depletion, as well as inhibition of cholesterol synthesis per se, enhances axon regeneration. Here, I discussed these findings and propose some possible underlying mechanisms. The latter would include possible disruptions to axon growth inhibitor signaling by lipid raft-localized receptors, as well as other yet unclear neuronal survival signaling process enhanced by cholesterol lowering or depletion.展开更多
A new chromone derivative, 3-[1- (2, 4, 6-trihydroxyphenyl) 3-di-(4-hydroxyphenyl) 1-propanone-2-yl] 5,7-dihydroxy-8-di(4-hydroxyphenyl)methyl-4H-1-benzopyran-4-one, named as isomohsenone was isolated from the roots o...A new chromone derivative, 3-[1- (2, 4, 6-trihydroxyphenyl) 3-di-(4-hydroxyphenyl) 1-propanone-2-yl] 5,7-dihydroxy-8-di(4-hydroxyphenyl)methyl-4H-1-benzopyran-4-one, named as isomohsenone was isolated from the roots of Stellera chamaejasme L. together with known chamaechromone. Its structure was determined by the analysis of MS and NMR data, especially 2D NMR spectra.展开更多
Conformational changes to 1,4-β-D-glucan cellobiohydrolase I (CBHI) in response to its binding with p-nitrophenyl β-D-cellobioside (PNPC) were analyzed by second-derivative fluorescence spectrometry at the saturatio...Conformational changes to 1,4-β-D-glucan cellobiohydrolase I (CBHI) in response to its binding with p-nitrophenyl β-D-cellobioside (PNPC) were analyzed by second-derivative fluorescence spectrometry at the saturation binding point. Irreversible changes to the configuration of PNPC during the course of the binding process were characterized by UV spectral analysis. Isothermal titration calorimetry (ITC) was used to determine the stoichiometry of binding (i.e. the number of molar binding sites) of PNPC to CBHI. Two points on the surface of the CBHI molecule interact with PNPC, and irreversible changes to the configuration of PNPC occur during its conversion to p-nitrophenyl (PNP). The ITC studies demonstrated that the binding of PNPC to CBHI is an irreversible process, in which heat is released, but where there is no reversible equilibrium between PNPC-CBHI and CBHI and PNPC. On the other hand, PNP and cellobiose need to be released from the PNPC-CBHI complex to facilitate the repeated binding of new PNPC molecules to the renewable CBHI molecules. Therefore, we speculate that the energy, which powers the configurational change of PNPC as it is converted to PNP, is generated from cyclic changes in the conformation of CBHI during the binding/de-sorption process. These new insights may provide a basis for a better understanding of the binding mechanism in enzyme-substrate interactions.展开更多
In the cancer research field, the preferred method for evaluating the proliferative activity of cancer cells in vivo is to measure DNA synthesis rates. The cellular proliferation rate is one of the most important canc...In the cancer research field, the preferred method for evaluating the proliferative activity of cancer cells in vivo is to measure DNA synthesis rates. The cellular proliferation rate is one of the most important cancer characteristics, and represents the gold standard of pathological diagnosis. Positron emission tomography (PET) has been used to evaluate in vivo DNA synthetic activity through visualization of enhanced nucleoside metabolism. However, methods for the quantitative measurement of DNA synthesis rates have not been fully clarified. Several groups have been engaged in research on 4′-[methyl-<sup>11</sup>C]-thiothymidine (<sup>11</sup>C-4DST) in an effort to develop a PET tracer that allows quantitative measurement of in vivo DNA synthesis rates. This mini-review summarizes the results of recent studies of the in vivo measurement of cancer DNA synthesis rates using <sup>11</sup>C-4DST.展开更多
基金Supported by the National Natural Science Foundation of China( No. 2 98710 14 ) and the Foundation of Doctor byL anzhou U niversit
文摘A novel La complex with methyl-2-pyridyl ketone benzoyl hydrazone has been synthesized and determined by single crystal X-ray diffraction. The crystal is monoclinic with space group C2/c, a =1 7081(3) nm, b =1 5660(3) nm, c =1 3512(3) nm, α=90 00°, β=94 39(1)°, γ=90 00°, V =3 6037(12) nm 3, Z =4 . The complex is a ten-coordinated one with a lanthanum ion surrounded by a N 4O 6 set. The crystal structure is stabilized by hydrogen bonds between water molecules and NO - 3 anions.
文摘Synthetic phosphoethanolamine(Pho-s)is a monophosphoester ester with anti-inflammatory and pro-apoptotic properties.Meclizine chloridrate(MC)is a histamine H1 receptor blocker that is also able to inhibit cellular respiration.However,MC does not inhibit cellular respiration in isolated mitochondria such as antimycin and rotenone.Methyl-β-cyclodextrin(MβCD)belongs to theβ-cyclodextrin family,which is capable of removing cholesterol from the plasma membrane.The aim of this study was to evaluate the proliferative effects of meclizine chloridrate and methyl-β-cyclodextrin compounds associated with synthetic phosphoethanolamine in a triple-negative human breast tumor line,MDA-MB-231 Cell viability of the tumor line and normal cells FN1 was evaluated by MTT colorimetric test;the production of free radicals was determined by lipoperoxidation(LPO)test;and the percentage of cell cycle phases and proliferative index was evaluated by flow cytometry.Cell viability demonstrated a significant decrease with the treatments of MβCD,MC and Pho-s associated with MC.The production of free radicals decreases significantly in all treatments.In addition,a significant increase of DNA fragment and decrease in G0/G1 cell cycle phase were observed in cellular percentage with concentrations of 20 and 30 mM of Pho-s in association with MC and MβCD,respectively.
基金supported by the National Natural Science of Foundation of China(No.21671094)
文摘Two N-donor ligands mediated Cd(Ⅱ) coordination polymers, namely,[Cd(L)(dmpz)2]n (1) and {[Cd(L)(atr)05(H20)](H2O)}n (2) (H2L = methyl-3-hydroxy-5-carboxy-2-thiophenecarboxylate, dmpz = 3,5-dimethylpyrazole, and atr= 4-amino-l,2,4-triazole), havebeen produced. Their structures were characterized by single-crystal X-ray diffraction analysis,elemental analyses and infrared spectra. Compound 1 possesses a one-dimensional (1D) chainstructure and is finally extended into a three-dimensional (3D) supramolecular architecturethough hydrogen bonding interactions. Compound 2 features a two-dimensional (2D) networkwith 4-connected sql topology based on dinuclear Cd(Ⅱ) clusters as nodes, which is alsoassembled into a 3D supramolecular architecture through hydrogen bonding interactions.Furthermore, compounds 1 and 2 exhibit high thermal stabilities and intense fluorescent emissionin the solid, and can be explored as potential luminescent materials.
文摘The syntheses of N-Methyl-14C benzyl amine and N-Methyl-14C benzyl nitrosamine are reported. Specific activities were approximately 920 MBq/mmol. Chemical and radiochemical purity checked by HPLC were more than 95%.
文摘An improved method for preparation of 4-methyl-2-phenyl piperazine and its derivatives with higher yield and inexpensive reagents was developed, the products were characterized by 1H-NMR and MS.
文摘The title complex, Cl3SnCH2CH(CH3)CO2CH3L (1), was synthesized by the reaction of methyl 2-methyl-3-trichlorostannylpropionate with benzylmethylsulfoxide (L) in solid state at room temperature and readily underwent transesterification into the corresponding analogues Cl3SnCH2CH(CH3)CO2RL when reacted with an alcohol ROH. The structural features of these compounds were described, and the possible mechanism of transesterification was suggested.
基金Supported by the National Natural Science Foundation of China (No. 20872149)
文摘A zinc(Ⅱ) compound [ZnCl2(mpcm)2](1,mpcm = methyl-3-pyridylcarbamate) was prepared by solvothermal reaction and characterized by elemental analysis,IR spectroscopy,TGA and single-crystal X-ray diffraction.The crystal is of monoclinic system,space group P21/n,C14H16ZnCl2N4O4,Mr = 440.58,a = 8.7893(7),b = 24.978(2),c = 9.2510(8),β = 109.318(1)°,V = 1916.6(3)3,Z = 4,θ = 1.63~25.20°,Dc = 1.527 g/cm3,μ = 1.585 mm-1,F(000) = 896,the final R = 0.0255 and wR = 0.0654 for 3080 observed reflections with Ⅰ 〉 2σ(Ⅰ).The zinc atom is four-coordinated by the pyridyl groups of two mpcm ligands and two chloride ions with a tetrahedral geometry.Two [ZnCl2(mpcm)2] subunits are held together by a pair of hydrogen bonds,forming a 32-membered macrocyclic dimer,which is further extended into a 3D tubular structure via hydrogen bonding.
基金support from the National Natural Science Foundation of China(No.50473036)
文摘Methyl-(γ-chloropropyl)dichlorosilane was synthesized under the catalysis of a silicasupported Karstedt-type catalyst. By orthogonal experimental design method, the optimum reaction parameters such as reactants ratio, reaction temperature and time, and the dosage of catalyst, were determined. At the optimum reaction condition the product yield reached 78.42%, which is higher than that reported in the literatures.
基金The authors are gratelbl for financial supports IYom the National Natural Science roundation of Chinathe Educational Commiss
文摘A new spectrofluorimetric method for determination of trace terbium based on its reaction with 2.6-his-(1'-phenyl-3'-methyl-5'- pyridinediacyl (H_2PMBPP) and N- cetylpyridium bromide (CPB). at an apparent pH=5.0 provided by a hexamethylenetetramine (5% w/w)-hydrochloric acid buffer,is propesed. The calibration graph is linear in the ran ge from
文摘Nine new derivatives of 7 β - (5- methyl- 1- aryl- 1H-1, 2, 3- triazoly- 4- carboxamido) cephalosporins were synthesized by acylction of 7 β -amino group of 7-ACA, 7-ADCA and 7-ACT with 5 -methsyl- 1 -aryl- 1 H- 1,2,3-triazoly-4-formyl chloride. The structure of the compounds were confirmed by elementray analysis IR, HNMR and FAB-MS. Some of them showed significant antibacterial activity
文摘The paper reports the synthetic procedure and character of Copper(II) binuclearcoordination compound of 1,4-bis-(1'-phenyl-3'-methyl-5'-pyrazolone Thenon-isothermal kinetics of thermal decomposition of the complex has been stUdied from the TG-DTGcurves by means of the Achar et al. and Coats-Redfern methods,the most probab1e kinetic equation canbe expressed as dofdtrAe -E / RT * l /(2Q).The corresponding kinetic compensation effect expressions arefound to be lnuA=0. 1794E+0. 1689.The non-isothermal thermal decomposition process of the complex isone-dimensional diffusion.But electrochemical studies of the complex(Cu2L'2)from cyclic voltamrnetriccurves by means of powder microelectrodes technique'',shows one two-electron irreversible process.
基金Supported by Earmarked Fund for Modern Agro-industry Technology Research System of China(CARS-49)Natural Science Foundation of Liaoning Province(201602408)~~
文摘DNA methylation is a critical epigenetic mechanism that influences gene transcription, genomic stability, X-chromosome inactivation and other factors, and appropriate DNA methylation is crucial in development. DNA methyltransferase 1 (DNMT1) plays an important role in maintaining the established methylation pattern during DNA replication. Although the effect of DNA methylation on embryonic development has been well known in vertebrates, little research has been carried out in invertebrates, especially in marine bivalves. In this study, the DNMT1 gene (MyDNMT1) was firstly identified from Mizuhopecten yessoensis. The full-length cDNA of MyDNMT1 was 5 039 bp, consisted of a 5' untranslated region (5'-UTR) of 79 bp, a 3' untranslated region (3'-UTR) of 199 bp, and a 4 761 bp open reading frame (ORF) encoding a peptide of 1 586 amino acids without a putative signal peptide. The relative mRNA expression level of MyDNMT1 was measured during the embryonic development of M. ydssoensis using real-time PCR, which revealed that the level at stage zygote and trochophore were significantly higher than that at other stages. We further examined the global DNA methylation during development by colorimetric method. The results showed that the methylation level was increased and reached the peak at blastula stage, then dramatically decreased, and fluctuated at early D-shaped larva stage. This study provided greater insight into the DNA methylation of embryonic development, which obtained a better understanding of the relationship between the DNA methylation and the embryonic development in bivalve mollusks.
文摘There are more than 250 kinds of Zanthoxylum plants in the world, of which about 40 species grow in China. In last 30 years, nearly 80 kinds of the plants have been studicd intensively and the results show that they are of different chemical compositions and various physiological actions, such as having anthelmintic action, bacteriostasis,
基金supported by the National Natural Science Foundation of China(21401097)
文摘One two-dimensional coordination polymer with a formula of {[Cd(L)(imidazole)(H2O)](H2O)}n(1) was obtained by the synthetic reactions in aqueous solution using a newly synthesized H2L(H2L = methyl-3-hydroxy-5-carboxy-2-thiophenecarboxylate) ligand.Compound1 crystallizes in monoclinic system,space group C2/c with a = 18.3176(11),b = 8.5366(9),c =8.4152(5)A,β = 101.789(6)°,V = 2797.1(3)A^3,Dc = 1.979 g/cm^3,C(10)H(12)N2O7SCd,Mr = 416.68 F(000) = 1648,μ = 1.745 mm^-1,F(000) = 1648,the final R = 0.0323 and wR = 0.0604 for 2604 observed reflections with I 〉 2s(I).Structure analyses reveal that the compound is constructed by dinuclear Cd(Ⅱ) clusters bridged by two hydroxyl oxygens of L^2-anions,which features a two-dimensional network with 4-connected sql topology.Furthermore,the compound exhibits high thermal stability and intense fluorescent emission,and could be explored for potentia luminescent materials.
文摘Cholesterol is biosynthesized by all animal cells. Beyond its metabolic role in steroidogenesis, it is enriched in the plasma membrane where it has key structural and regulatory functions. Cholesterol is thus presumably important for post-injury axon regrowth, and this notion is supported by studies showing that impairment of local cholesterol reutilization impeded regeneration. However, several studies have also shown that statins, inhibitors of 3-hydroxy-3-methylglutaryl-Co A reductase, are enhancers of axon regeneration, presumably acting through an attenuation of the mevalonate isoprenoid pathway and consequent reduction in protein prenylation. Several recent reports have now shown that cholesterol depletion, as well as inhibition of cholesterol synthesis per se, enhances axon regeneration. Here, I discussed these findings and propose some possible underlying mechanisms. The latter would include possible disruptions to axon growth inhibitor signaling by lipid raft-localized receptors, as well as other yet unclear neuronal survival signaling process enhanced by cholesterol lowering or depletion.
文摘A new chromone derivative, 3-[1- (2, 4, 6-trihydroxyphenyl) 3-di-(4-hydroxyphenyl) 1-propanone-2-yl] 5,7-dihydroxy-8-di(4-hydroxyphenyl)methyl-4H-1-benzopyran-4-one, named as isomohsenone was isolated from the roots of Stellera chamaejasme L. together with known chamaechromone. Its structure was determined by the analysis of MS and NMR data, especially 2D NMR spectra.
基金the National Natural Science Foundation of China (Grant Nos. 30370013 and 30500007)
文摘Conformational changes to 1,4-β-D-glucan cellobiohydrolase I (CBHI) in response to its binding with p-nitrophenyl β-D-cellobioside (PNPC) were analyzed by second-derivative fluorescence spectrometry at the saturation binding point. Irreversible changes to the configuration of PNPC during the course of the binding process were characterized by UV spectral analysis. Isothermal titration calorimetry (ITC) was used to determine the stoichiometry of binding (i.e. the number of molar binding sites) of PNPC to CBHI. Two points on the surface of the CBHI molecule interact with PNPC, and irreversible changes to the configuration of PNPC occur during its conversion to p-nitrophenyl (PNP). The ITC studies demonstrated that the binding of PNPC to CBHI is an irreversible process, in which heat is released, but where there is no reversible equilibrium between PNPC-CBHI and CBHI and PNPC. On the other hand, PNP and cellobiose need to be released from the PNPC-CBHI complex to facilitate the repeated binding of new PNPC molecules to the renewable CBHI molecules. Therefore, we speculate that the energy, which powers the configurational change of PNPC as it is converted to PNP, is generated from cyclic changes in the conformation of CBHI during the binding/de-sorption process. These new insights may provide a basis for a better understanding of the binding mechanism in enzyme-substrate interactions.
基金Supported by A Grant-in-Aid for Scientific Research from the Japan Society for the Promotion of Science,No.(B)25293271
文摘In the cancer research field, the preferred method for evaluating the proliferative activity of cancer cells in vivo is to measure DNA synthesis rates. The cellular proliferation rate is one of the most important cancer characteristics, and represents the gold standard of pathological diagnosis. Positron emission tomography (PET) has been used to evaluate in vivo DNA synthetic activity through visualization of enhanced nucleoside metabolism. However, methods for the quantitative measurement of DNA synthesis rates have not been fully clarified. Several groups have been engaged in research on 4′-[methyl-<sup>11</sup>C]-thiothymidine (<sup>11</sup>C-4DST) in an effort to develop a PET tracer that allows quantitative measurement of in vivo DNA synthesis rates. This mini-review summarizes the results of recent studies of the in vivo measurement of cancer DNA synthesis rates using <sup>11</sup>C-4DST.