谷氨酰胺高产菌株在不同NH_4^+浓度下的基因差异表达

Differential Gene Expression of the High Glutamine Producing Strain of Arthrobacter globiformis in the Different NH_4^+ Concentration

GH15菌株在高NH_4^+浓度下能够积累过量的谷氨酰胺,并且随着NH_4^+浓度的增加,谷氨酰胺的产量逐渐增加,但谷氨酸的产量却逐渐降低,这表明该菌株在不同NH_4^+浓度下其高胞内的氮代谢及调控行为有很大的改变。利用抑制消减杂交技术分别构建了NH_4^+菌株在高NH_4^+浓度下和低NH_4^+浓度下的基因表达抑制消减文库。通过对文库的测序得到了35个差异表达的基因。这些差异基因主要是细胞生长相关基因、能量代谢基因以及氨基酸合成代谢相关的基因,我们认为正是这些基因差异导致该菌株在高NH_4^+下高产谷氨酰胺。

Arthrobacter globiformis strain GH15 can excessively accumulate glutamine in high NH4＋ concentration, and glutamine yield can gradually increase in a certain range with the increase of NH4＋, while the yield of glutamate can reduce accordingly, which indicates that nitrogen metabolism and regulation in the cell of GH15 should have dramatic changes in high NH4＋ concentrations. The gene expression subtractive suppression hy- bridization library in the different NH4＋ concentration was constructed in this research, 35 differentially expressed genes were obtained and sequenced, which focused on the genes that mainly related to cell growth, energy metabolism and metabolism of amino acids. We believed that it is the differences of these genes lead to the strain produces high glutamine yield in high NH4＋ concentration.