MANGANESE AND DEFENSES AGAINST OXYGEN-TOXICITY IN LACTOBACILLUS-PLANTARUM
MANGANESE AND DEFENSES AGAINST OXYGEN-TOXICITY IN LACTOBACILLUS-PLANTARUM
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DOI：
10.1128/jb.145.1.442-451.1981
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发表时间：
1981-01-01
影响因子：
3.2
通讯作者：
FRIDOVICH, I
中科院分区：
文献类型：
--
作者：
ARCHIBALD, FS;FRIDOVICH, I
L. plantarum在葡萄糖上的对数期生长期间是耐氧的，但在多元醇上是专性需氧菌。呼吸是抗氰化物的，在某些条件下与积累的毫摩尔浓度的过氧化氢。在葡萄糖上，在没有O2的情况下观察到最佳生长。L.的提取物plantarum不催化还原NAD还原百草枯，但白花丹醌（5-羟基-2-甲基-1，4-萘醌）很容易被还原。这种提取物在NADH加白花丹素的存在下产生O2-。在葡萄糖存在下，白花丹素引起完整细胞的呼吸速率增加10倍，并且还造成依赖于葡萄糖和O2的活力丧失。虽然L. plantarum缺乏真正的超氧化物歧化酶活性，这种生物体在其对高压O2的抗性和对白花丹素的氧依赖性致死性方面与含超氧化物歧化酶的物种相当。L. plantarum需要Mn丰富的媒体和积极积累Mn（II）。可溶性提取物含有9 μ g Mn/mg蛋白质，并且该Mn的75-90%是可透析的。这种提取物表现出可透析和EDTA-可降解的能力，以吸收O2-。这O2-清除活性是由于透析锰（II）存在于这些提取物中，可以模仿氯化锰。在锰丰富的培养基中生长的细胞富含可透析的锰，并且比在锰缺乏的培养基中生长的细胞对O2毒性和对O2依赖的白花丹醌毒性更有抗性。L. plantarum没有表现出对Fe的营养需求，并且这些细胞中存在很少或没有Fe，即使当它们在富含Fe的培养基中生长时。L.因此，plantarum似乎使用毫摩尔水平的Mn（II）转化为MnO 2-，就像大多数其他生物使用微摩尔水平的超氧化物歧化酶一样。
L. plantarum is aerotolerant during log-phase growth on glucose, but is an obligate aerobe on polyols. Respiration was cyanide resistant and under certain conditions was associated with the accumulation of millimolar concentrations of H2O2. On glucose, optimal growth was observed in the absence of O2. Extracts of L. plantarum did not catalyze the reduction of paraquat by reduced NAD, but plumbagin (5-hydroxy-2-methyl-1,4-naphthoquinone) was readily reduced. Such extracts produced O2- in the presence of NADH plus plumbagin. Plumbagin caused a 10-fold increase in the rate of respiration of intact cells in the presence of glucose and also imposed a loss of viability which was dependent upon glucose and 02. Although extracts of L. plantarum were devoid of true superoxide dismutase activity, this organism was comparable to superoxide dismutase-containing species in its resistance toward hyperbaric O2 and toward the oxygen-dependent lethality of plumbagin. L. plantarum required Mn-rich media and actively accumulated Mn(II). Soluble extracts contain .apprx. 9 .mu.g of Mn/mg of protein and 75-90% of this Mn was dialyzable. Such extracts exhibited a dialyzable and EDTA-inhibitable ability to scavenge O2-. This O2--scavenging activity was due to the dialyzable Mn(II) present in these extracts and could be mimicked by MnCl2. Cells grown in Mn-rich media were enriched in dialyzable Mn and were more resistant toward O2 toxicity and toward the O2-dependent plumbagin toxicity than were cells grown in Mn-deficient media. L. plantarum exhibited no nutritional requirement for Fe and little or no Fe was present in these cells, even when they were grown in Fe-rich media. L. plantarum thus appears to use millimolar levels of Mn(II) to scavenge O2-, much as most other organisms use micromolar levels of superoxide dismutases.