Lee K Y, Joseph C M, Meeks J C
Dept. of Bacteriology, University of California, Davis 95616.
Antonie Van Leeuwenhoek. 1988;54(4):345-55. doi: 10.1007/BF00393525.
Glutamine synthetase (GS) is the primary NH4+ assimilating enzyme of cyanobacteria. The specific activities and cellular protein concentration of GS in symbiotic cyanobacteria associated with the water fern Azolla caroliniana were determined and compared to free-living cultures of Nostoc sp. strain 7801, a strain originally isolated from symbiotic association with the bryophyte Anthoceros punctatus. Both the in vitro specific activity and concentration of GS in symbiotic cyanobacteria separated from A. caroliniana were approximately 3-fold lower than the free-living Nostoc sp. strain 7801 culture. These results imply depressed synthesis of GS by the symbiont associated with A. caroliniana.
谷氨酰胺合成酶（GS）是蓝细菌主要的NH4+同化酶。测定了与卡罗来纳满江红共生的蓝细菌中GS的比活性和细胞蛋白浓度，并与原从与苔藓植物斑点角苔共生关系中分离出的念珠藻属7801菌株的自由生活培养物进行了比较。从卡罗来纳满江红中分离出的共生蓝细菌中GS的体外比活性和浓度均比自由生活的念珠藻属7801菌株培养物低约3倍。这些结果表明与卡罗来纳满江红相关的共生体中GS的合成受到抑制。
