AIM: Bacillary dysentery caused by Shigella flexneriis still a threat to human health. Of four invasion plasmid antigen proteins (IpaA, B,C and D), IpaC plays an important role in the pathogenicity of this pathogen. T...AIM: Bacillary dysentery caused by Shigella flexneriis still a threat to human health. Of four invasion plasmid antigen proteins (IpaA, B,C and D), IpaC plays an important role in the pathogenicity of this pathogen. The purpose of this study was to investigate the proteins interacting with IpaC in the host cell during the pathogenic process of this disease.
METHODS: By applying two-hybrid system, the bait plasmid containing ipaC gene was constructed and designated pGBKr-ipaC. The bait plasmid was transformed AH109, and proved to express IpaC and then HeLa cDNA library plasmids were introduced into the above transformed AHL09. The transformation mixture was plated on medium lacking Trp, Leu, and His in the initial screen, then restreaked on medium lacking Trp, Leu, His and Ade. Colonies growing on the selection medium were further assayed for β-galactosidase activity. BLAST was carried out in the database after sequencing the inserted cDNA of the positive library plasmid.
RESULTS: Among the 2x106 transformants, 64 positive clones were obtained as determined by activation of His,Ade and LacZ reporter genes. Sequence analysis revealed that cDNA inserts of two colonies were highly homologous to a known human protein, RanBPM.
CONCLUSION: These results provide evidence that IpaC may be involved in the invasion process of S. flexneri by interacting with RanBPM, and RanBPM is most likely to be the downstream target of IpaC in the cascade events of S.flexneri infection.展开更多
The design problem of an integrated power and attitude control system （IPACS） for spacecrafts is investigated. A Lyapunov-typed IPACS controller is designed for a spacecraft equipped with 4 flywheels （3 orthogonal ...The design problem of an integrated power and attitude control system （IPACS） for spacecrafts is investigated. A Lyapunov-typed IPACS controller is designed for a spacecraft equipped with 4 flywheels （3 orthogonal ＋ 1 skew）. This controller keeps in the nonlinear properties of original systems, so the control result can be more precise. A control law of the flywheels is also proposed to accomplish the attitude control and energy storage simultaneously. Aiming at the limitations existing in the power conversion characteristic and the wheel＇s motor, a new strategy of energy management is proposed. The strategy can not only make the charged/discharged energy reaching balance in each orbital period, but also sufficiently utilize the power provided by the solar arrays. Therefore, the size and mass of solar arrays can be decreased, and the cost of spacecraft can be economized. A simulation example illustrates the validity of the designed IPACS.展开更多
基金Capital"248"Key Innovation Project(H010210360119)State key Research and Development Project(G1999054103)
文摘AIM: Bacillary dysentery caused by Shigella flexneriis still a threat to human health. Of four invasion plasmid antigen proteins (IpaA, B,C and D), IpaC plays an important role in the pathogenicity of this pathogen. The purpose of this study was to investigate the proteins interacting with IpaC in the host cell during the pathogenic process of this disease.
METHODS: By applying two-hybrid system, the bait plasmid containing ipaC gene was constructed and designated pGBKr-ipaC. The bait plasmid was transformed AH109, and proved to express IpaC and then HeLa cDNA library plasmids were introduced into the above transformed AHL09. The transformation mixture was plated on medium lacking Trp, Leu, and His in the initial screen, then restreaked on medium lacking Trp, Leu, His and Ade. Colonies growing on the selection medium were further assayed for β-galactosidase activity. BLAST was carried out in the database after sequencing the inserted cDNA of the positive library plasmid.
RESULTS: Among the 2x106 transformants, 64 positive clones were obtained as determined by activation of His,Ade and LacZ reporter genes. Sequence analysis revealed that cDNA inserts of two colonies were highly homologous to a known human protein, RanBPM.
CONCLUSION: These results provide evidence that IpaC may be involved in the invasion process of S. flexneri by interacting with RanBPM, and RanBPM is most likely to be the downstream target of IpaC in the cascade events of S.flexneri infection.
文摘The design problem of an integrated power and attitude control system （IPACS） for spacecrafts is investigated. A Lyapunov-typed IPACS controller is designed for a spacecraft equipped with 4 flywheels （3 orthogonal ＋ 1 skew）. This controller keeps in the nonlinear properties of original systems, so the control result can be more precise. A control law of the flywheels is also proposed to accomplish the attitude control and energy storage simultaneously. Aiming at the limitations existing in the power conversion characteristic and the wheel＇s motor, a new strategy of energy management is proposed. The strategy can not only make the charged/discharged energy reaching balance in each orbital period, but also sufficiently utilize the power provided by the solar arrays. Therefore, the size and mass of solar arrays can be decreased, and the cost of spacecraft can be economized. A simulation example illustrates the validity of the designed IPACS.
