Under a given condition of crystallization, dark brown short rhombohedron crystals could be obtained from Δ nifZ MoFe protein purified from a nifZ deleted mutant strain of Azotobacter vinelandii Lipmann....Under a given condition of crystallization, dark brown short rhombohedron crystals could be obtained from Δ nifZ MoFe protein purified from a nifZ deleted mutant strain of Azotobacter vinelandii Lipmann. Systematic studies on the effect of concentrations of PEG 8000,MgCl 2, NaCl,Tris and buffer pH on the crystallization and crystal growth of the protein showed that the protein could not be crystallized in lower concentrations of the chemicals and lower buffer pH. A large amount of smaller crystals of the protein appeared in a week with gradual increasing in the chemical concentrations and pH≥8.0. When the chemical concentrations were further increased, the time for crystallization was increased and a few high grade crystals of larger size were formed. If the concentrations of the chemicals were continuously increased, many crystals with smaller size, and, sometimes of poor quality appeared again and eventually ceased to produce any crystals. The optimal concentration for each of the above mentioned chemicals varies with other variable factors. Only one bigger crystal (both of the longest two sides: 0.16 mm) could be obtained in a hanging drop of protein sample when the concentrations of PEG 8000, MgCl 2, NaCl,Tris and protein were kept at 1.86%, 300 mmol/L, 400 mmol/L, 53 mmol/L and 4.64 g/L , respectively, with Tris buffer pH 8.2.展开更多
[ObJective] The research aimed to determine the geographic distribution map of system of Rana dybowskii. [Method] Four morphologic indices （body length, body weight, forelimb length, hindlimb length） of eight geogra...[ObJective] The research aimed to determine the geographic distribution map of system of Rana dybowskii. [Method] Four morphologic indices （body length, body weight, forelimb length, hindlimb length） of eight geographical populations of R.dybowskii which naturally distribute in Changhai Mountain and Xiaoxing＇an Mountain were measured. Measure results were variance analyzed and cluster analyzed. [Result] Variance analysis showed： the genetic branching among the Dongfanghong male population（ belongs to Wandashan） and Xiaoxing＇an Mountain male population and Changbai Mountain male population were significantly different （P〈0.05） ; the genetic branching between the Hebei female population （belongs to Xiaoxing＇an Mountain） and Changbai Mountain female population was significantly different （P〈0.05 ）. Cluster analysis showed ： male R.dybowskii can be divided into three groups ： the first group included Quanyang, Tianbei, Chaoyang and Ddkouqin, the second group included Tieli and Anshan, the third group included Dongfanghong; and the female R. dybowskii can be divided into three groups ： the first group included Quanyang and Chaoyang, the second group included Tianbei and Dakouqin, the third group included Hebei. [Condusion] The paper deduced that the Sanjiang Plain was the geographical origin center ofR. dybowskii which radiated to Changbai Mountain and Xiaoxing＇an Mountain along the adverse current of Songhua River basin, therefore, the current distribution pattern of R. dybowskii was formed.展开更多
文摘Under a given condition of crystallization, dark brown short rhombohedron crystals could be obtained from Δ nifZ MoFe protein purified from a nifZ deleted mutant strain of Azotobacter vinelandii Lipmann. Systematic studies on the effect of concentrations of PEG 8000,MgCl 2, NaCl,Tris and buffer pH on the crystallization and crystal growth of the protein showed that the protein could not be crystallized in lower concentrations of the chemicals and lower buffer pH. A large amount of smaller crystals of the protein appeared in a week with gradual increasing in the chemical concentrations and pH≥8.0. When the chemical concentrations were further increased, the time for crystallization was increased and a few high grade crystals of larger size were formed. If the concentrations of the chemicals were continuously increased, many crystals with smaller size, and, sometimes of poor quality appeared again and eventually ceased to produce any crystals. The optimal concentration for each of the above mentioned chemicals varies with other variable factors. Only one bigger crystal (both of the longest two sides: 0.16 mm) could be obtained in a hanging drop of protein sample when the concentrations of PEG 8000, MgCl 2, NaCl,Tris and protein were kept at 1.86%, 300 mmol/L, 400 mmol/L, 53 mmol/L and 4.64 g/L , respectively, with Tris buffer pH 8.2.
文摘[ObJective] The research aimed to determine the geographic distribution map of system of Rana dybowskii. [Method] Four morphologic indices （body length, body weight, forelimb length, hindlimb length） of eight geographical populations of R.dybowskii which naturally distribute in Changhai Mountain and Xiaoxing＇an Mountain were measured. Measure results were variance analyzed and cluster analyzed. [Result] Variance analysis showed： the genetic branching among the Dongfanghong male population（ belongs to Wandashan） and Xiaoxing＇an Mountain male population and Changbai Mountain male population were significantly different （P〈0.05） ; the genetic branching between the Hebei female population （belongs to Xiaoxing＇an Mountain） and Changbai Mountain female population was significantly different （P〈0.05 ）. Cluster analysis showed ： male R.dybowskii can be divided into three groups ： the first group included Quanyang, Tianbei, Chaoyang and Ddkouqin, the second group included Tieli and Anshan, the third group included Dongfanghong; and the female R. dybowskii can be divided into three groups ： the first group included Quanyang and Chaoyang, the second group included Tianbei and Dakouqin, the third group included Hebei. [Condusion] The paper deduced that the Sanjiang Plain was the geographical origin center ofR. dybowskii which radiated to Changbai Mountain and Xiaoxing＇an Mountain along the adverse current of Songhua River basin, therefore, the current distribution pattern of R. dybowskii was formed.
