Department of Microbiology, Faculty of Biology, Lomonosov Moscow State University, Leninskie Gory 1/12, Moscow, Russia 119234.
Curr Microbiol. 2012 Oct;65(4):375-83. doi: 10.1007/s00284-012-0168-6. Epub 2012 Jun 26.
Methanogenic archaeon Methanobrevibacter arboriphilus (strains AZ and DH1), which is a strict anaerobic microorganism not able to synthesize heme, possessed a very high catalase activity in the presence of 20-50 μM hemin in a growth medium. We investigated the effect of various oxidative stresses (hydrogen peroxide and oxygenation) on M. arboriphilus cells grown on the standard nutrient medium supplemented with 0.1 % yeast extract, and on the same medium supplemented with hemin. It was demonstrated that 30 μM hemin had a very significant positive effect on the resistance of M. arboriphilus strains to H(2)O(2) and O(2) stresses because of 30- to 40-fold increase of heme catalase activity. Thus, hydrogen peroxide (0.6-1.2 mM) or oxygen (3-5 %) had a strong negative impact on low-catalase cultures grown in the hemin-free standard medium, whereas the presence of 30 μM hemin in the medium results in a high yield of biomass even under conditions of four times stronger H(2)O(2) and two times stronger O(2) stresses. The intracellular catalase activity reached a high level in 30-60 min after hemin was added to the nutrient medium, but the activity already increased about 5-7-fold in 6 min after hemin addition. Our experimental data suggest that exogenous hemin provides an effective antioxidative defense in representatives of the genus Methanobrevibacter, specially playing an important role in the puromycin-insensitive formation of the active heme-containing catalase from presynthesized apoenzyme and heme.
产甲烷古菌 Methanobrevibacter arboriphilus（菌株 AZ 和 DH1）是一种严格的厌氧微生物，不能合成血红素，但在生长培养基中存在 20-50 μM 血红素时，其具有非常高的过氧化氢酶活性。我们研究了各种氧化应激（过氧化氢和氧化）对在补充有 0.1%酵母提取物的标准营养培养基中生长的 Methanobrevibacter arboriphilus 细胞以及在补充血红素的相同培养基中生长的 Methanobrevibacter arboriphilus 菌株的影响。结果表明，由于血红素过氧化氢酶活性增加了 30-40 倍，30 μM 血红素对 Methanobrevibacter arboriphilus 菌株对 H2O2 和 O2 应激的抗性具有非常显著的积极影响。因此，过氧化氢（0.6-1.2 mM）或氧气（3-5%）对无血红素标准培养基中低过氧化氢酶培养物具有很强的负面影响，而培养基中存在 30 μM 血红素即使在过氧化氢和氧气应激分别增强 4 倍和 2 倍的条件下，也能获得高生物量。血红素添加到营养培养基后 30-60 分钟内细胞内过氧化氢酶活性达到高水平，但血红素添加后 6 分钟内活性已增加约 5-7 倍。我们的实验数据表明，外源性血红素为 Methanobrevibacter 属的代表提供了有效的抗氧化防御，特别是在嘌呤霉素不敏感的情况下，从预合成的脱辅基酶和血红素形成活性含血红素的过氧化氢酶方面发挥重要作用。
