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Jue‐Long Wang Chiang‐Ting Chou Kang Liu Wei‐Zhe Liang Jin‐Shiung Cheng Hong‐Tai Chang I‐Shu Chen Ti Lu Chun‐Chi Kuo Chia‐Cheng Yu Pochuen Shieh Daih‐Huang Kuo Fu‐An Chen Chung‐Ren Jan 《Journal of biochemical and molecular toxicology》2016,30(11):539-547
The effect of protriptyline on Ca2+ physiology in human hepatoma is unclear. This study explored the effect of protriptyline on [Ca2+]i and cytotoxicity in HepG2 human hepatoma cells. Protriptyline (50–150 μM) evoked [Ca2+]i rises. The Ca2+ entry was inhibited by removal of Ca2+. Protriptyline‐induced Ca2+ entry was confirmed by Mn2+‐induced quench of fura‐2 fluorescence. Except nifedipine, econazole, SKF96365, GF109203X, and phorbol 12‐myristate 13 acetate did not inhibit Ca2+ entry. Treatment with the endoplasmic reticulum Ca2+ pump inhibitor 2,5‐di‐tert‐butylhydroquinone (BHQ) inhibited 40% of protriptyline‐induced response. Treatment with protriptyline abolished BHQ‐induced response. Inhibition of phospholipase C (PLC) suppressed protriptyline‐evoked response by 70%. At 20–40 μM, protriptyline killed cells which was not reversed by the Ca2+ chelator 1,2‐bis(2‐aminophenoxy)ethane‐N,N,N′,N′‐tetraacetic acid‐acetoxymethyl ester (BAPTA/AM). Together, in HepG2 cells, protriptyline induced [Ca2+]i rises that involved Ca2+ entry through nifedipine‐sensitive Ca2+ channels and PLC‐dependent Ca2+ release from endoplasmic reticulum. Protriptyline induced Ca2+‐independent cell death. 相似文献
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The sequence cato encoding catechol 1,2-dioxygenase from Candida tropicalis JH8 was cloned, sequenced, and expressed in Escherichia coli. The sequence cato contained an ORF of 858?bp encoding a polypeptide of 285?amino acid residues. The recombinant catechol 1,2-dioxygenase exists as a homodimer structure with a subunit molecular mass of 32 KD. Recombinant catechol 1,2-dioxygenase was unstable below pH 5.0 and stable from pH 7.0 to 9.0; its optimum pH was at 7.5. The optimum temperature for the enzyme was 30°C, and it possessed a thermophilic activity within a broad temperature range. Under the optimal conditions with catechol as substrate, the Km and Vmax of recombinant catechol 1,2-dioxygenase were 9.2?µM and 0.987?µM/min, respectively. This is the first article presenting cloning and expressing in E. coli of catechol 1,2-dioxygenase from C. tropicalis and characterization of the recombinant catechol 1,2-dioxygenase. 相似文献
997.
Jirong Wang Chaojun Wang Chengyun Xu Xiaokai Wu Dun Hong Wei Shi Ying Gong Haixiao Chen Fanxin Long Ximei Wu 《Genetics》2016,202(3):1055-1069
Endochondral ossification consists of successive steps of chondrocyte differentiation, including mesenchymal condensation, differentiation of chondrocytes, and hypertrophy followed by mineralization and ossification. Loss-of-function studies have revealed that abnormal growth plate cartilage of the Cdc42 mutant contributes to the defects in endochondral bone formation. Here, we have investigated the roles of Cdc42 in osteogenesis and signaling cascades governing Cdc42-mediated chondrogenic differentiation. Though deletion of Cdc42 in limb mesenchymal progenitors led to severe defects in endochondral ossification, either ablation of Cdc42 in limb preosteoblasts or knockdown of Cdc42 in vitro had no obvious effects on bone formation and osteoblast differentiation. However, in Cdc42 mutant limb buds, loss of Cdc42 in mesenchymal progenitors led to marked inactivation of p38 and Smad1/5, and in micromass cultures, Cdc42 lay on the upstream of p38 to activate Smad1/5 in bone morphogenetic protein-2-induced mesenchymal condensation. Finally, Cdc42 also lay on the upstream of protein kinase B to transactivate Sox9 and subsequently induced the expression of chondrocyte differential marker in transforming growth factor-β1-induced chondrogenesis. Taken together, by using biochemical and genetic approaches, we have demonstrated that Cdc42 is involved not in osteogenesis but in chondrogenesis in which the BMP2/Cdc42/Pak/p38/Smad signaling module promotes mesenchymal condensation and the TGF-β/Cdc42/Pak/Akt/Sox9 signaling module facilitates chondrogenic differentiation. 相似文献
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Marjorie R. Lundgren Pascal‐Antoine Christin Emmanuel Gonzalez Escobar Brad S. Ripley Guillaume Besnard Christine M. Long Paul W. Hattersley Roger P. Ellis Richard C. Leegood Colin P. Osborne 《Plant, cell & environment》2016,39(9):1874-1885
C4 photosynthesis is a complex trait resulting from a series of anatomical and biochemical modifications to the ancestral C3 pathway. It is thought to evolve in a stepwise manner, creating intermediates with different combinations of C4‐like components. Determining the adaptive value of these components is key to understanding how C4 photosynthesis can gradually assemble through natural selection. Here, we decompose the photosynthetic phenotypes of numerous individuals of the grass Alloteropsis semialata, the only species known to include both C3 and C4 genotypes. Analyses of δ13C, physiology and leaf anatomy demonstrate for the first time the existence of physiological C3–C4 intermediate individuals in the species. Based on previous phylogenetic analyses, the C3–C4 individuals are not hybrids between the C3 and C4 genotypes analysed, but instead belong to a distinct genetic lineage, and might have given rise to C4 descendants. C3 A. semialata, present in colder climates, likely represents a reversal from a C3–C4 intermediate state, indicating that, unlike C4 photosynthesis, evolution of the C3–C4 phenotype is not irreversible. 相似文献
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