Ouyang Jianping, Guo Wenbin, Li Bo, Gu Li, Zhang Huijun, Xinhua Chen Huijun
Microbiol Res. 2016 Jan;182:163-8. doi: 10.1016/j.micres.2015.02.004.
Acidithiobacillus ferrooxidans is a chemolithoautotrophic acidophile that oxidizes ferrous iron or sulfur compounds to obtain energy in the presence of various ions. To investigate the potassium ion response of A. ferrooxidans, we conducted a proteomics analysis. We identified eight proteins that were differentially expressed in the presence of high potassium concentration, including four up-regulated and four down-regulated proteins. Transcription levels of the genes encoding differential expressed proteins were subsequently analyzed by Northern blot in the presence of high potassium concentration. Among the up-regulated proteins, GDP-mannose 4,6-dehydratase, ribose 5-phosphate isomerase A and ribose-phosphate pyrophosphokinase were known to be implicated in the synthesis of glycocalyx, suggesting that the formation of glycocalyx might be involved in the A. ferrooxidans response to high potassium concentration. Thickening of the glycocalyx layer was also observed in cells cultivated under high potassium concentration via transmission electronic microscopy (TEM) analysis. Among the down-regulated proteins, ATP synthase F1 delta subunit and ATP synthase F1 beta subunit were two important components of ATP synthase. ATP synthase (P-ATPase) is directly linked to the transport of potassium into the cell, thus Acidithiobacillus ferrooxidans might just reduce the quantity of ATP synthase to offset the high potassium level in the culture medium. Therefore, the results obtained here provide some new clues to improve our understanding of the response of A. ferrooxidans to high potassium concentration.
氧化亚铁硫杆菌是一种化能自养嗜酸菌，在各种离子存在的情况下，它通过氧化亚铁或硫化合物来获取能量。为了研究氧化亚铁硫杆菌对钾离子的反应，我们进行了蛋白质组学分析。我们鉴定出了8种在高钾浓度下差异表达的蛋白质，其中4种上调，4种下调。随后，在高钾浓度条件下，通过Northern印迹分析了编码差异表达蛋白质的基因的转录水平。在上调的蛋白质中，GDP - 甘露糖4,6 - 脱水酶、核糖5 - 磷酸异构酶A和核糖磷酸焦磷酸激酶已知与糖被的合成有关，这表明糖被的形成可能参与了氧化亚铁硫杆菌对高钾浓度的反应。通过透射电子显微镜（TEM）分析还观察到，在高钾浓度下培养的细胞中糖被层增厚。在下调的蛋白质中，ATP合酶F1δ亚基和ATP合酶F1β亚基是ATP合酶的两个重要组成部分。ATP合酶（P - ATPase）直接与钾离子进入细胞的运输相关，因此氧化亚铁硫杆菌可能只是减少ATP合酶的数量以抵消培养基中的高钾水平。因此，这里获得的结果为增进我们对氧化亚铁硫杆菌对高钾浓度反应的理解提供了一些新线索。
