Arginine Deiminase in Staphylococcus epidermidis Functions To Augment Biofilm Maturation through pH Homeostasis
Arginine Deiminase in Staphylococcus epidermidis Functions To Augment Biofilm Maturation through pH Homeostasis
复制标题
DOI：
10.1128/jb.00051-14
复制
发表时间：
2014-06-01
影响因子：
3.2
通讯作者：
Fey, P. D.
中科院分区：
文献类型：
--
作者：
Lindgren, J. K.;Thomas, V. C.;Fey, P. D.
构建精氨酸脱亚胺酶（arcA1和arcA2）内的等位基因置换突变体，以评估精氨酸脱亚胺酶（ADI）途径在表皮葡萄球菌1457的有机酸抗性和生物膜形成中的功能。生长依赖性酸化测定（pH类似于5.0至类似于5.2）确定缺乏精氨酸脱亚胺酶活性的菌株1457（1457 Δ ADI）在葡萄糖耗尽后和在精氨酸存在下比野生型的活力显著更低。然而，在个体1457 Δ arcA1（天然）或Δ arcA2（精氨酸分解代谢移动的元件[ACME]衍生）突变体中，未观察到活力差异，表明天然和ACME衍生的ADI在S.表皮此外，流式细胞术和电子顺磁共振光谱的结果表明，有机酸应激导致氧化应激，可以部分获救的铁螯合剂联吡啶。总的来说，这些结果表明，羟基自由基的形成是部分负责细胞死亡通过有机酸应力和ADI衍生的氨功能，以抵消这种酸应力。最后，静态生物膜测定确定，与菌株1457和arcA1和arcA2单突变体相比，菌株1457 Δ ADI在生长120小时后的活力、氨合成和pH值降低。据推测，通过ADI途径的氨合成对于降低含有高浓度有机酸的特定微生态中的pH胁迫是重要的。
Allelic replacement mutants were constructed within arginine deiminase (arcA1 and arcA2) to assess the function of the arginine deiminase (ADI) pathway in organic acid resistance and biofilm formation of Staphylococcus epidermidis 1457. A growth-dependent acidification assay (pH similar to 5.0 to similar to 5.2) determined that strain 1457 devoid of arginine deiminase activity (1457 Delta ADI) was significantly less viable than the wild type following depletion of glucose and in the presence of arginine. However, no difference in viability was noted for individual 1457 Delta arcA1 (native) or Delta arcA2 (arginine catabolic mobile element [ACME]-derived) mutants, suggesting that the native and ACME-derived ADIs are compensatory in S. epidermidis. Furthermore, flow cytometry and electron paramagnetic resonance spectroscopy results suggested that organic acid stress resulted in oxidative stress that could be partially rescued by the iron chelator dipyridyl. Collectively, these results suggest that formation of hydroxyl radicals is partially responsible for cell death via organic acid stress and that ADI-derived ammonia functions to counteract this acid stress. Finally, static biofilm assays determined that viability, ammonia synthesis, and pH were reduced in strain 1457 Delta ADI following 120 h of growth in comparison to strain 1457 and the arcA1 and arcA2 single mutants. It is hypothesized that ammonia synthesis via the ADI pathway is important to reduce pH stress in specific microniches that contain high concentrations of organic acids.