BIMODAL PATTERN OF KILLING OF DNA-REPAIR-DEFECTIVE OR ANOXICALLY GROWN ESCHERICHIA-COLI BY HYDROGEN-PEROXIDE
BIMODAL PATTERN OF KILLING OF DNA-REPAIR-DEFECTIVE OR ANOXICALLY GROWN ESCHERICHIA-COLI BY HYDROGEN-PEROXIDE
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DOI：
10.1128/jb.166.2.519-527.1986
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发表时间：
1986-05-01
影响因子：
3.2
通讯作者：
LINN, S
中科院分区：
文献类型：
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作者：
IMLAY, JA;LINN, S
过氧化氢对大肠杆菌K - 12的两种杀伤模式可以区分开来。在过氧化氢浓度为1到2毫摩尔时，第一种杀伤模式达到最大。在更高浓度下，杀伤速率约为最大速率的一半，且与过氧化氢浓度无关，但与暴露时间呈一级反应。第一种杀伤模式在过氧化氢攻击期间需要活跃的新陈代谢，并且它导致存活的细胞和被攻击杀死的细胞都出现不依赖于sfiA的丝状化。这种杀伤模式在xth、polA、recA和recB菌株中增强，并且在所有菌株中都因一种未知的、缺氧诱导的细胞功能而加速。一个同时携带xth和recA突变的菌株似乎仅在有氧条件下发生自发的第一种杀伤。第一种杀伤似乎是由DNA损伤导致的，而这种DNA损伤在有氧生长期间通常以一种低的、非致死水平发生。第二种杀伤在较高剂量的过氧化氢下发生，并且对过氧化氢浓度和暴露时间都呈现多击依赖性。第二种杀伤不需要活跃的新陈代谢，并且被杀死的细胞不会丝状化，尽管存活的细胞表现出剂量依赖性的生长延迟。具有DNA修复缺陷的菌株对第二种杀伤并不特别敏感。
Two modes of killing of Escherichia coli K-12 by hydrogen peroxide can be distinguished. Mode-one killing was maximal with hydrogen peroxide at a concentration of 1 to 2 mM. At higher concentrations the killing rate was approximately half maximal and was independent of H2O2 concentration but first order with respect to exposure time. Mode-one killing required active metabolism during the H2O2 challenge, and it resulted in sfiA-independent filamentation of both cells which survived and those which were killed by the challenge. This mode of killing was enhanced in xth, polA, recA, and recB strains and was accelerated in all strains by an unidentified, anoxia-induced cell function. A strain carrying both xth and recA mutations appeared to undergo spontaneous mode-one killing only under aerobic conditions. Mode-one killing appeared to result from DNA damage which normally occurs at a low, nonlethal level during aerobic growth. Mode-two killing occurred at higher doses of H2O2 and exhibited a multihit dependence on both H2O2 concentration and exposure time. Mode-two killing did not require the active metabolism, and killed cells did not filament, although survivors demonstrated a dose-dependent growth lag. Strains with DNA-repair defects were not especially susceptible to mode-two killing.