摘要
通过不同装液量、不同氧化还原状态的碳源和添加NA D+的前体烟酸来调控大肠杆菌胞内的能荷、还原力水平,研究胞内核苷酸和聚唾液酸合成之间的关系。结果表明,聚唾液酸合成量越高,胞内UTP含量越低、UMP含量越高;同时,合成UTP、CTP消耗大量ATP使胞内能荷水平较低。与其他碳源的发酵相比,以山梨醇为碳源时,由于胞内NADH水平的提高使菌体合成的聚唾液酸量最高。添加烟酸可以提高胞内的NAD+水平,导致胞内的氧化水平提高,从而使胞内还原产物如聚唾液酸、琥珀酸、乳酸的产量降低甚至消失。
Different medium volumes, carbon sources with varied redox states and adding nicotinic acid, and the precursor of NAD＋were used to adjust the intracellular energy charge and reduction of Escherichia coli in order to investigate the relationships between biosynthesis of polysialic acid and intracellular nucleotides. The results showed that the higher the production of polysialic acid was, the lower UTP was, but higher UMP was. Meanwhile, energy charge level was lower because the synthesis of UTP and CTP consumed a lot of ATP. Using sorbitol as carbon source, more polysialic acid was produced than those of fermentation with glucose, xylose and sodium gluconate due to the increase of NADH. Addition of nicotinic acid to the fermentation medium elevated intracellular NAD＋, which led to the raise of intracellular oxidative stress, sequentially the decrease of the reducing metabolites such as polysialic acid, succinate and lactate, and even the vanish of them.
出处
《生物技术通报》
CAS
CSCD
北大核心
2015年第9期209-217,共9页
Biotechnology Bulletin
基金
国家"863"计划项目(2012AA021505)
江苏省自然科学基金项目(BK2011158)
关键词
大肠杆菌
聚唾液酸
能荷
核苷酸
氧化还原势
Escherichia coli
polysialic acid
energy charge
nucleotides
redox potential
