A protease-resistant catalase, KatA, released upon cell lysis during stationary phase is essential for aerobic survival of a Pseudomonas aeruginosa oxyR mutant at low cell densities
A protease-resistant catalase, KatA, released upon cell lysis during stationary phase is essential for aerobic survival of a Pseudomonas aeruginosa oxyR mutant at low cell densities
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DOI：
10.1128/jb.182.16.4557-4563.2000
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发表时间：
2000-08-01
影响因子：
3.2
通讯作者：
Ochsner, UA
中科院分区：
文献类型：
--
作者：
Hasset, DJ;Alsabbagh, E;Ochsner, UA
铜绿假单胞菌oxyR突变体显着敏感H2 O2，尽管具有野生型过氧化氢酶活性。氧依赖性oxyR表型还包括无法在Luria肉汤中有氧连续稀释中存活和抵抗氨基糖苷类。将oxyR突变体在其自身的用过的培养物上清液（其含有主要的过氧化氢酶KatA）中连续稀释后铺板，或在厌氧条件下铺板允许存活。KatA对十二烷基硫酸钠、蛋白酶K、胃蛋白酶、胰蛋白酶、胰凝乳蛋白酶和中性粒细胞蛋白酶组织蛋白酶G具有耐药性。当提供反式和组成型表达时，OxyR调节基因katB，ahpB和ahpCF不能恢复连续稀释缺陷和H2 O2抗性;只有oxyR本身可以做到这一点。需氧稀释缺陷可以补充，部分，只有ahpB和ahpCF，这表明后者的基因产物可以具有过氧化氢酶样活性。发现需氧Luria肉汤通过自氧化产生类似于1.2 μ M H2 O2 min（-1）的水平，该水平足以杀死连续稀释的oxyR和oxyR katA细菌，并解释了需氧连续稀释缺陷背后的分子机制。综上所述，我们的结果表明，OxyR的失活使铜绿假单胞菌对H2 O2和氨基糖苷类药物非常敏感，这两种药物是临床和环境上重要的抗菌剂。
A Pseudomonas aeruginosa oxyR mutant was dramatically sensitive to H2O2, despite possessing wild-type catalase activity. Oxygen-dependent oxyR phenotypes also included an inability to survive aerobic serial dilution in Luria broth and to resist aminoglycosides. Plating the oxyR mutant after serial dilution in its own spent culture supernatant, which contained the major catalase KatA, or under anaerobic conditions allowed for survival. KatA was resistant to sodium dodecyl sulfate, proteinase K, pepsin, trypsin, chymotrypsin and the neutrophil protease cathepsin G. When provided in trans and expressed constitutively, the OxyR-regulated genes katB, ahpB, and ahpCF could not restore both the serial dilution defect and H2O2 resistance; only oxyR itself could do so. The aerobic dilution defect could be complemented, in part, by only ahpB and ahpCF, suggesting that the latter gene products could possess a catalase-like activity. Aerobic Luria broth was found to generate similar to 1.2 mu M H2O2 min(-1) via autoxidation, a level sufficient to kill serially diluted oxyR and oxyR katA bacteria and explain the molecular mechanism behind the aerobic serial dilution defect. Taken together, our results indicate that inactivation of OxyR renders P. aeruginosa exquisitely sensitive to both H2O2 and aminoglycosides, which are clinically and environmentally important antimicrobials.