检索结果-南通市图书馆

Constitutive activation of AtMEK5,a MAPK kinase,induces salicylic acid- independent cell death in Arabidopsis thaliana

在线全文

学校读者我要写书评

暂无评论

引用

Chinese Science Bulletin 2004年第24期49卷 2594-2600页

作者： LIUHongxia WANGYing ZHOUTianhong SUNYujing LIUGuoqin rendongtao StateKeyLaboratoryofPlantPhysiologyandBiochemistry CollegeofBiologicalSciencesChinaAgriculturalUniversityBeijing100094China

AtMEK5 DD is an active mutant of AtMEK5, a MAP kinase kinase in Arabidopsis. Induction of AtMEK5 DD expression in transgenic plants leads to activation of 44 and 48 kD MAPKs and causes a rapid cell death. To compare the cell death induced by the expression of AtMEK5 DD with the HR-cell death induced by avirulence pathogen infection, we analyzed the activation of downstream MAP Kinase and induction of PR genes expression in permanent transgenic Arabidopsis plants. In-gel kinase activity assay revealed that the infection of Pseudomonas syringae DC3000 harboring Avr Rpt2 gene also lead to activation of 44 and 48 kD MAPKs. PAL, PR1 and PR5 were strongly induced in plants undergo- ing HR-cell death caused by the infection of P. syringae DC3000, while only the expression of PR5 was strongly in- duced in transgenic plants expressing AtMEK5 DD protein. NahG protein in AtMEK5 ×NahG plants cannot suppress DD the cell death induced by AtMEK5 . And AtMEK5 DD DD pro- tein expressed AtMEK5 ×NahG plants showed no signifi- DD cant change in salicylic acid (SA) level. All these suggest that the cell death induced by the activation of AtMEK5 is sali- cylic acid-independent.

关键词： AtMEK5 MAPK致活酶水杨酸细胞病原体植物自我保护系统

Cloning and expression of AtPLC6, a gene encoding a phosphatidylinositol-specific phospholipase C in Arabidopsis thaliana

在线全文

学校读者我要写书评

暂无评论

引用

Chinese Science Bulletin 2004年第6期49卷 567-573页

作者： XUXiaojing CAOZhixiang LIUGuoqin MadanK.Bhattacharrya~ rendongtao StateKeyLabofPlantPhysiologyandBiochemistry.CollegeofBiologicalSciences.ChinaAgriculturalUniversity.Beijing100094.China AgronomyDepartment IowaStateUniversity.Ames.lowa500111010USA

A full-length cDNA clone corresponding to a putative phosphatidylinositol-specific phospholipase C (PI- PLC) was isolated from Arabidopsis thaliana by screening a cDNA library and using RT-PCR strategy. The cDNA, des-ignated AtPLC6, encodes a putative polypeptide of 578 amino acid residues with a calculated molecular mass of 66251.84 D and a pI of 7.24. The sequence analysis indicates that the polypeptide contains X, Y, EF-hand and C2 domains. The overall structure of putative AtPLC6 protein, like other plant PI-PLCs, is most similar to that of mammalian PLCd. The recombinant AtPLC6 protein expressed in E. coli was able to hydrolyze phosphatidylinositol 4,5-biophosphate (PIP2) to generate inositol 1,4,5-trisphate (IP3) and 1,2-diacylglycerol (DAG). The protein hydrolyzes PIP2 in a Ca2+-dependent manner and the optimum concentration of Ca2+ is 10 mmol/L. These results suggested that AtPLC6 gene encodes a genuine PI-PLC. Northern blot analysis showed that the AtPLC6 gene is expressed at low level in all examined tissues, such as roots, stems, leaves, flowers, siliques and seedlings under normal growth conditions. The gene is strongly induced under low temperature and weakly induced under various stresses, such as ABA, high-salt stress and heat. These results sug-gested that AtPLC6 might be involved in the signal-trans- duction pathways of cold responses of the plants.

关键词：克隆基因表达 AtPLC6 基因编码磷脂酰丝氨酸脱羧酶 PIPLC 阿拉伯芥

Measurements of leucocyte membrane elasticity based on the optical tweezers

在线全文

学校读者我要写书评

暂无评论

引用

Chinese Science Bulletin 2003年第5期48卷 503-508页

作者： GUOHonglian CAOQinhong rendongtao LIUGuoqing DUANJianfa LIZhaolin ZHANGDaozhong HANXuehai OpticalPhysicsLaboratory InstituteofPhysicsandCenterforCondensedMatterPhysicsChineseAcademyofSciencesBeijing100080China StateKeyLoboratoryofPlantPhysiologyandBiochemistry CollegeofBiologySciencesChinaAgriculturalUniversityBeijing100094China StateKeyLaboratoryofBiomacromolecles InstitueofBiophysicsChineseAcademyofSciencesBeijing100101China StateKeyLaboratoryofBiomacromolecles InstituteofBiophysicsChineseAcademyofSciencesBeijing100101China

A 1-mm in diameter polystyrene bead coated with lectin is trapped by optical tweezers which is formed by a focused laser beam (740 nm). A leucocyte adhered to the bottom of sample cell is chosen to close to the trapped bead. When their stable combination is confirmed, the leucocyte is displaced by moving the sample stage. A tether is then formed between the trapped bead and the membrane. The force acting on the tether is measured by a detector equipped on the optical tweezers system. The deformation of the membrane is diverse in different contact conditions. When the contact area is small, the tether is very thin and the force on it is 7.4 pN (10-12 N), while the tether is much thicker un-der a larger contact area and its corresponding force is about 14 pN. It is presumed that the latter is related to the defor-mation of cytoskeleton.

关键词：白细胞细胞膜弹力测量光学镊子系统细胞骨架血液细胞