Regulation of autolysins in teichuronic acid-containing Bacillus subtilis cells
Regulation of autolysins in teichuronic acid-containing Bacillus subtilis cells
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DOI：
10.1046/j.1365-2958.2002.02872.x
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发表时间：
2002-05-01
影响因子：
3.6
通讯作者：
Doyle, RJ
中科院分区：
文献类型：
--
作者：
Calamita, HG;Doyle, RJ
生长在磷酸盐饥饿下的枯草芽孢杆菌细胞在诱导磷壁酸(TUA)合成的同时抑制磷壁酸(TA)的合成。含TA和含TUA的壁细胞的周转率相似，说明自溶素的功能相似，提示自溶功能的调节可能是相似的。在本研究中，利用异硫氰酸荧光素(FITC)-葡聚糖来探测壁面的pH，证明了壁面基质中存在低pH值。第二个探针，阳离子铁蛋白(CF)，用于观察细胞表面质子化。含有TA或TUA的枯草杆菌细胞悬浮液仅在加入质子动能消散剂后才与CF聚集。用FITC-葡聚糖标记的含枯草杆菌的呼吸细胞几乎没有荧光。相反，用氮气断电的细胞表现出的荧光强度明显更大。在含有TA和TUA的枯草杆菌细胞中加入含有浓缩自溶素的细胞壁蛋白提取物，研究了质子力对自溶活性的影响。只有在加入叠氮钠后，含TUA和TA的细胞才能裂解。这些数据表明，在正常生长过程中，含TuA的枯草杆菌细胞壁被质子化，质子化动力影响含TuA和含TA的B.subtilis细胞的自溶调节。
Bacillus subtilis cells grown under phosphate starvation induce teichuronic acid (TUA) synthesis while simultaneously repressing teichoic acid synthesis (TA). The turnover rates of TA-containing and TUA-containing walls are similar, indicating that autolysin function is similar and suggesting that modulation of autolytic function may be similar. In this study, it is demonstrated, utilizing fluorescein isothiocyanate (FITC)-dextran to probe the wall pH, that a low pH exists in the wall matrix. A second probe, cationized ferritin (CF), was used to observe cell surface protonation. Suspensions of B. subtilis cells containing either TA or TUA were aggregated with CF only after the addition of a protonmotive force-dissipating agent. Respiring B. subtilis TUA-containing cells labelled with FITC-dextran exhibited little fluorescence. Conversely, fluorescence intensities exhibited by cells de-energized with nitrogen gas were significantly greater. The effects of protonmotive force on autolytic activity were studied by adding cell wall protein extract containing concentrated autolysin to exponentially growing TA-containing and TUA-containing B. subtilis cells. Both TUA-containing and TA-containing cells were lysed only after the addition of sodium azide. These data suggest that during normal growth the wall of TUA-containing B. subtilis cells is protonated, and protonmotive force influences autolytic regulation in both TUA-containing and TA-containing B. subtilis cells.