CdGd2 （WO4）4 -δ single crystal was grown using the Czochralski＇s method. The crystal structure was tetragonal seheelite with lattice parameters a = b = 0.5203 nm and c = 1. 1359 nm. There were vacancies of （WO4）...CdGd2 （WO4）4 -δ single crystal was grown using the Czochralski＇s method. The crystal structure was tetragonal seheelite with lattice parameters a = b = 0.5203 nm and c = 1. 1359 nm. There were vacancies of （WO4）^2- , therefore, there were some Gd^2＋ ions. Langevin paramagnetism and anisotropy were observed from the δ-T curves at room temperature. The susceptibility X//was 3.5018×10^-3, and X⊥ was 3.4403× 10^-2. The anisotropy was also observed in the electron spin resonance （ESR） experiments. The anisotropic Land6 factors were g//= 2. 1333 and g~ = 2. 8411. The direction of easy magnetization was in the α-b plane. Anisotropic paramagnetic Curie constants C//and C⊥ were not only related to macroscopic a that was observed through the experiment, but were also related to J⊥ and J//, which were the microscopic quantum numbers of the Gd^2＋ and Gd^3｜ ions. Based on the detailed analyses, the proportion of 36.8% of Gd^3＋ ions to 63.2% of Gd^2＋ ions in the Gd ions of the CdGd2（WO4）4-δ crystal was calculated, and δ was 0.638 in the single crystal.展开更多
Cyclic dimeric GMP(c-di-GMP)has emerged as the nucleotide second messenger regulating both development and antibiotic production in high-GC,Gram-positive streptomycetes.Here,a diguanylate cyclase(DGC),CdgD,encoded by ...Cyclic dimeric GMP(c-di-GMP)has emerged as the nucleotide second messenger regulating both development and antibiotic production in high-GC,Gram-positive streptomycetes.Here,a diguanylate cyclase(DGC),CdgD,encoded by SCO5345 from the model strain Streptomyces coelicolor,was functionally identified and characterized to be involved in c-di-GMP synthesis through genetic and biochemical analysis.cdgD overexpression resulted in significantly reduced production of actinorhodin and undecylprodigiosin,as well as completely blocked sporulation or aerial mycelium formation on two different solid media.In the cdgD-overexpression strain,intracellular c-di-GMP levels were 13-27-fold higher than those in the wild-type strain.In vitro enzymatic assay demonstrated that CdgD acts as a DGC,which could efficiently catalyze the synthesis of c-di-GMP from two GTP molecules.Heterologous overproduction of cdgD in two industrial Streptomyces strains could similarly impair developmental transitions as well as antibiotic biosynthesis.Collectively,our results combined with previously reported data clearly demonstrated that c-di-GMP-mediated signalling pathway plays a central and universal role in the life cycle as well as secondary metabolism in streptomycetes.展开更多
基金Project supported by the National Natural Science Foundation of China (69977005)
文摘CdGd2 （WO4）4 -δ single crystal was grown using the Czochralski＇s method. The crystal structure was tetragonal seheelite with lattice parameters a = b = 0.5203 nm and c = 1. 1359 nm. There were vacancies of （WO4）^2- , therefore, there were some Gd^2＋ ions. Langevin paramagnetism and anisotropy were observed from the δ-T curves at room temperature. The susceptibility X//was 3.5018×10^-3, and X⊥ was 3.4403× 10^-2. The anisotropy was also observed in the electron spin resonance （ESR） experiments. The anisotropic Land6 factors were g//= 2. 1333 and g~ = 2. 8411. The direction of easy magnetization was in the α-b plane. Anisotropic paramagnetic Curie constants C//and C⊥ were not only related to macroscopic a that was observed through the experiment, but were also related to J⊥ and J//, which were the microscopic quantum numbers of the Gd^2＋ and Gd^3｜ ions. Based on the detailed analyses, the proportion of 36.8% of Gd^3＋ ions to 63.2% of Gd^2＋ ions in the Gd ions of the CdGd2（WO4）4-δ crystal was calculated, and δ was 0.638 in the single crystal.
基金supported by the National Natural Science Foundation of China (31630003, 31570072 and 31770088)the Science and Technology Commission of Shanghai Municipality (18ZR1446700)the National Science and Technology Major Project (2017ZX09101003-006-012)
文摘Cyclic dimeric GMP(c-di-GMP)has emerged as the nucleotide second messenger regulating both development and antibiotic production in high-GC,Gram-positive streptomycetes.Here,a diguanylate cyclase(DGC),CdgD,encoded by SCO5345 from the model strain Streptomyces coelicolor,was functionally identified and characterized to be involved in c-di-GMP synthesis through genetic and biochemical analysis.cdgD overexpression resulted in significantly reduced production of actinorhodin and undecylprodigiosin,as well as completely blocked sporulation or aerial mycelium formation on two different solid media.In the cdgD-overexpression strain,intracellular c-di-GMP levels were 13-27-fold higher than those in the wild-type strain.In vitro enzymatic assay demonstrated that CdgD acts as a DGC,which could efficiently catalyze the synthesis of c-di-GMP from two GTP molecules.Heterologous overproduction of cdgD in two industrial Streptomyces strains could similarly impair developmental transitions as well as antibiotic biosynthesis.Collectively,our results combined with previously reported data clearly demonstrated that c-di-GMP-mediated signalling pathway plays a central and universal role in the life cycle as well as secondary metabolism in streptomycetes.
