首页 | 本学科首页   官方微博 | 高级检索  
     


Regulation of methylammonium/ammonium transport in the unicellular cyanobacterium Synechococcus R-2 (PCC 7942)
Authors:Samy Boussiba  Jane Gibson
Affiliation:The Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel;Section of Biochemistry, Molecular and Cell Biology, Division of Biological Sciences, Cornell University, Ithaca, NY 14853, U.S.A.
Abstract:The unicellular cyanobacterium Synechococcus R-2 (PCC 7942) took up 14CH3NH+3 at least 10 times faster after growth with NO3 than with NH+4 as nitrogen source. When NH+4-grown cells were transferred to medium containing NO3, the ability to accumulate 14CH3NH+3 required approximately 6 h for maximal expression. Chloramphenicol (50 μg · ml−1) completely prevented the rise in transport ability. Transport by nitrate-grown cells incubated in 2 mM NH4Cl or CH3NH3Cl, with or without NO3, continued at high rates for 2–3 h, but fell to zero by about 5 h incubation in light. Methylammonium, or the γ-methyl glutamic amide derived from it, thus may also serve as a signal for repression; however, externally added glutamine stimulated rather than repressed 14CH3NH+3 transport. Changes in 14CH3NH+3 uptake rates brought about by NH+4 were confined to these slow effects, and to competition for entry into the cell.
Keywords:Methylammonium transport    Synechococcus R-2    (regulation)
本文献已被 ScienceDirect 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号