In response to salt stress, cyanobacteria increases the gene expression of Na+/H+ antiporter and K+ uptake system proteins and subsequently accumulate compatible solutes. However, alterations in the concentrations of metabolic intermediates functionally related to the early stage of the salt stress response have not been investigated. The halophilic cyanobacterium Synechococcus sp. PCC 7002 was subjected to salt shock with 0.5 and 1 M NaCl, then we performed metabolomics analysis by capillary electrophoresis/mass spectrometry (CE/MS) and gas chromatography/mass spectrometry (GC/MS) after cultivation for 1, 3, 10, and 24 h. Gene expression profiling using a microarray after 1 h of salt shock was also conducted. We observed suppression of the Calvin cycle and activation of glycolysis at both NaCl concentrations. However, there were several differences in the metabolic changes after salt shock following exposure to 0.5 M and 1 M NaCl: (i): the main compatible solute, glucosylglycerol, accumulated quickly at 0.5 M NaCl after 1 h but increased gradually for 10 h at 1 M NaCl; (ii) the oxidative pentose phosphate pathway and the tricarboxylic acid cycle were activated at 0.5 M NaCl; and (iii) the multi-functional compound spermidine greatly accumulated at 1 M NaCl. Our results show that Synechococcus sp. PCC 7002 acclimated to different levels of salt through a salt stress response involving the activation of different metabolic pathways.

中文翻译：

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嗜盐蓝藻Syechococcus sp。中的短期时间代谢行为。盐冲击后应变PCC 7002。

响应盐胁迫，蓝细菌会增加Na + / H +反向转运蛋白和K +摄取系统蛋白的基因表达，并随后累积相容的溶质。但是，尚未研究与盐胁迫反应早期阶段功能相关的代谢中间体浓度的变化。嗜盐蓝细菌Synechococcus sp.。将PCC 7002置于0.5和1 M NaCl的盐溶液中震荡，然后在分别培养1，3，10，10和10倍后，通过毛细管电泳/质谱（CE / MS）和气相色谱/质谱（GC / MS）进行了代谢组学分析。和24小时 还进行了盐冲击1小时后使用微阵列进行的基因表达谱分析。我们观察到在两种NaCl浓度下，卡尔文循环的抑制和糖酵解的激活。然而，暴露于0.5 M和1 M NaCl的盐冲击后，代谢变化有几个差异：（i）：主要相容性溶质葡萄糖基甘油在1 h后以0.5 M NaCl迅速积累，而在1 M后逐渐增加10 h氯化钠; （ii）在0.5M NaCl下活化氧化戊糖磷酸途径和三羧酸循环；（iii）多功能化合物亚精胺在1M NaCl中大量积累。我们的结果表明，Synechococcus sp。PCC 7002通过涉及不同代谢途径活化的盐胁迫反应，使盐适应了不同水平的盐。（ii）在0.5M NaCl中活化氧化戊糖磷酸途径和三羧酸循环；（iii）多功能化合物亚精胺在1M NaCl中大量积累。我们的结果表明，Synechococcus sp。PCC 7002通过涉及不同代谢途径活化的盐胁迫反应，使盐适应了不同水平的盐。（ii）在0.5M NaCl中活化氧化戊糖磷酸途径和三羧酸循环；（iii）多功能化合物亚精胺在1M NaCl中大量积累。我们的结果表明，Synechococcus sp。PCC 7002通过涉及不同代谢途径活化的盐胁迫反应，使盐适应了不同水平的盐。