Scuola di Scienze Agrarie, Forestali, Alimentari e Ambientali, Università degli Studi della Basilicata, Potenza, Italy.
Dipartimento di Scienze, Università degli Studi della Basilicata, Potenza, Italy.
Int J Food Microbiol. 2018 Sep 2;280:66-77. doi: 10.1016/j.ijfoodmicro.2018.05.004. Epub 2018 May 8.
Catalases reduce oxidative stress by degrading hydrogen peroxide to molecular oxygen and water. The presence of heme-dependent or manganese-dependent catalases was observed for a long time in lactic acid bacteria (LAB) but, to date, knowledge on the factors affecting gene expression and enzymatic functionality are limited to a very few strains. In this study, the effect of atmosphere of incubation (not aerated static growth vs aerated shaken growth) and supplementation with Fe, hemin, Mn or their combinations on the catalase production of respiration-competent strain Lactobacillus casei N87 was evaluated using a 2 factorial design. Kinetics of growth, enzymatic activity, tolerance of oxidative stress and expression of heme- and Mn-catalase genes were assessed. A phylogenetic analysis of heme- and Mn-catalase sequences retrieved for all published LAB genomes was performed. The presence of cofactors, especially when combined, improved biomass production in L. casei N87 in both aerated and not aerated conditions. The genome of L. casei N87 harboured sequences for both catalases and hemin and Mn supplementation was crucial for gene expression and enzyme functionality. Iron and oxygen had an additive stimulatory effect. Tolerance of oxidative stress was higher in aerated cultures supplemented with hemin and/or Mn, because of high catalase activities. The presence of both enzymes was confirmed in other respirative strains of L. casei. Clustering of catalase sequences reflected in most of cases the phylogenetic distance between LAB genomes, but in other cases significant differences were found within the same genus, indicating a different evolutionary history. The occurrence of both genes is rare in LAB genomes. The exploitation of LAB with both heme- and Mn-catalases may ensure protection from oxidative stress in different conditions and may be relevant for several food (reduction of oxidative processes on food components) and health (prevention of human diseases) related applications.
过氧化氢酶通过将过氧化氢降解为分子氧和水来减少氧化应激。很长一段时间以来，人们一直在乳酸杆菌 (LAB) 中观察到血红素依赖性或锰依赖性过氧化氢酶的存在，但迄今为止，关于影响基因表达和酶功能的因素的知识仅限于极少数菌株。在这项研究中，使用 2 因子设计评估了培养气氛（不充气静态生长与充气摇瓶生长）和补充铁、血红素、锰或它们的组合对呼吸活性菌株干酪乳杆菌 N87 过氧化氢酶生产的影响。评估了生长动力学、酶活性、氧化应激耐受性和血红素和 Mn 过氧化氢酶基因的表达。对所有已发表的 LAB 基因组中检索到的血红素和 Mn 过氧化氢酶序列进行了系统发育分析。当组合使用时，辅因子的存在，特别是在充气和不充气条件下，都提高了干酪乳杆菌 N87 的生物量生产。干酪乳杆菌 N87 的基因组包含两种过氧化氢酶和血红素的序列，血红素和锰的补充对于基因表达和酶功能至关重要。铁和氧具有相加的刺激作用。在补充血红素和/或锰的充气培养物中，由于过氧化氢酶活性较高，对氧化应激的耐受性更高。在其他呼吸性干酪乳杆菌菌株中也证实了这两种酶的存在。过氧化氢酶序列的聚类在大多数情况下反映了 LAB 基因组之间的系统发育距离，但在某些情况下，在同一属内发现了显著差异，表明它们具有不同的进化历史。这两种基因的存在在 LAB 基因组中很少见。利用具有血红素和 Mn 过氧化氢酶的 LAB 可能确保在不同条件下免受氧化应激的影响，并且可能与几种与食品（减少食品成分的氧化过程）和健康（预防人类疾病）相关的应用相关。
