Investigating Catalase Activity Through Hydrogen Peroxide Decomposition by Bacteria Biofilms in Real Time Using Scanning Electrochemical Microscopy
Investigating Catalase Activity Through Hydrogen Peroxide Decomposition by Bacteria Biofilms in Real Time Using Scanning Electrochemical Microscopy
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DOI：
10.1021/ac402475m
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发表时间：
2014-01-07
影响因子：
7.4
通讯作者：
Zoski, Cynthia G.
中科院分区：
文献类型：
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作者：
Abucayon, Erwin;Ke, Neng;Zoski, Cynthia G.
通过扫描电化学显微镜 (SECM) 实时研究共生或独立菌株的费氏弧菌（γ-变形杆菌-弧菌科）细菌生物膜上方的 1 mM 散装溶液中过氧化氢分解的过氧化氢酶活性。过氧化氢酶活性（以 348 秒内每分钟分解的微摩尔过氧化氢为单位）被发现随每个生物膜的孵育时间而变化，与液体培养物中细菌的相应生长曲线相关。相同孵育时间（1 至 12 小时）内，共生生物膜的平均过氧化氢酶活性为 0.28 +/- 0.07 μmol H2O2/min，自由生活生物膜的平均过氧化氢酶活性为 0.31 +/- 0.07 μmol H2O2/min，表明过氧化氢酶活性相似。基于 Comsol Multiphysics 模拟拟合实验生物膜数据的计算表明，单个细菌每秒大约分解 (3 +/- 1) x 10(6) 个过氧化氢分子，这表明存在高活性过氧化氢酶。在生长培养基中，当外部过氧化氢浓度低至 1 nM 时，自生生物膜和共生生物膜的过氧化氢酶活性均增强了 2 倍，这意味着响应氧化应激的机制相似。
Catalase activity through hydrogen peroxide decomposition in a 1 mM bulk solution above Vibrio fischeri (gamma-Protebacteria-Vibrionaceae) bacterial biofilms of either symbiotic or free-living strains was studied in real time by scanning electrochemical microscopy (SECM). The catalase activity, in units of micromoles hydrogen peroxide decomposed per minute over a period of 348 s, was found to vary with incubation time of each biofilm in correlation with the corresponding growth curve of bacteria in liquid culture. Average catalase activity for the same incubation times ranging from 1 to 12 h was found to be 0.28 +/- 0.07 mu mol H2O2/min for the symbiotic biofilms and 0.31 +/- 0.07 mu mol H2O2/min for the free-living biofilms, suggesting similar catalase activity. Calculations based on Comsol Multiphysics simulations in fitting experimental biofilm data indicated that approximately (3 +/- 1) x 10(6) molecules of hydrogen peroxide were decomposed by a single bacterium per second, signifying the presence of a highly active catalase. A 2-fold enhancement in catalase activity was found for both free-living and symbiotic biofilms in response to external hydrogen peroxide concentrations as low as 1 nM in the growth media, implying a similar mechanism in responding to oxidative stress.