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首页> 外文学位 >Characterization of the Hydrogen Peroxide Stress Responses of Bifidobacterium longum and Bifidobacterium animalis subsp. lactis.
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Characterization of the Hydrogen Peroxide Stress Responses of Bifidobacterium longum and Bifidobacterium animalis subsp. lactis.

机译：长双歧杆菌和动物双歧杆菌亚种的过氧化氢胁迫响应的表征。乳酸菌。

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摘要

Consumer interest in probiotic bifidobacteria is increasing, but industry efforts to secure high cell viability are undermined by the sensitivity of these anaerobes to oxidative stress during food production or storage. In this study, we examined the physiological and transcriptional stress responses of three strains of Bifidobacterium longum and three strains of Bifidobacterium animalis subsp. lactis to hydrogen peroxide (H2O2). Intrinsic and inducible H2O2 resistance was determined for each strain, and results showed B. longum subsp. infantis ATCC 15697 had the highest level of intrinsic H2O2 resistance. Inducible H2O2 resistance was detected in four strains, B. longum strains NCC2705 and D2957, B. animalis subsp. lactis strains RH-1 and BL-04. We then examined the transcriptional responses of B. animalis subsp. lactis strains, BL-04 and DSM10140, and B. longum strains NCC2705 and D2957 to H2O2 exposure. Transcriptional analysis was performed on cells exposed to a sub-lethal H2O 2 concentration for 5, 20, or 60 min compared to an untreated control. B. animalis subsp. lactis BL-04 showed differential expression (DE) in 158 genes after 5 min, and 30 genes after 60 min. Surprisingly, no significant DE genes were detected in B. animalis subsp. lactis DSM10140 at either time. Although the strains are virtually identical genetically, genomic data suggested differences in H2O2 stress resistance might be related to the function of long chain fatty acid-coA ligase. To address this hypothesis, membrane fatty acids were isolated and analyzed by GC-MS. Results confirmed the two strains had significantly different lipid profiles, which could affect membrane fluidity and, potentially, transduction of stress signals. Data for the B. longum strains showed NCC2705 had 316 DE genes after the 5-min treatment and 131 DE genes after the 20-min treatment. In contrast, the D2957 strain had only 24 and 116 DE genes after the 5- and 20-min treatments, respectively. These data indicate that intrinsic and inducible resistance to hydrogen peroxide is strain specific, and suggest that for some strains, sublethal H2O2 treatments and cell membrane modifications might help increase cell resistance to oxidative damage during production and storage of probiotic-containing foods.
机译：消费者对益生菌双歧杆菌的兴趣正在增加，但是在食品生产或存储过程中，这些厌氧菌对氧化应激的敏感性削弱了确保高细胞生存力的行业努力。在这项研究中，我们检查了三株长双歧杆菌和三株动物双歧杆菌亚种的生理和转录应激反应。乳酸转化为过氧化氢（H2O2）。确定每个菌株的内在和诱导的H2O2抵抗力，结果显示长双歧杆菌亚种。婴儿ATCC 15697具有最高的内在H2O2抵抗力水平。在四个菌株，长双歧杆菌菌株NCC2705和D2957，动物双歧杆菌亚种中检测到诱导的H2O2抗性。乳酸菌株RH-1和BL-04。然后，我们检查了动物双歧杆菌亚种的转录反应。乳酸菌BL-04和DSM10140，以及长双歧杆菌NCC2705和D2957对H2O2的暴露。与未处理的对照相比，对暴露于亚致死H2O 2浓度的细胞进行了5、20或60分钟的转录分析。 B.动物亚种乳酸BL-04在5分钟后显示158个基因的差异表达（DE），在60分钟后显示30​​个基因的差异表达。令人惊讶的是，在动物双歧杆菌亚种中未检测到显着的DE基因。任一时间均为乳酸DSM10140。尽管菌株在遗传上实际上是相同的，但是基因组数据表明H2O2胁迫抗性的差异可能与长链脂肪酸-coA连接酶的功能有关。为了解决该假设，分离了膜脂肪酸并通过GC-MS进行了分析。结果证实这两种菌株具有明显不同的脂质谱，这可能影响膜的流动性，并可能影响应力信号的传导。长双歧杆菌菌株的数据显示，NCC2705在5分钟处理后具有316 DE基因，在20分钟处理后具有131 DE基因。相比之下，D2957菌株在5分钟和20分钟处理后分别只有24和116个DE基因。这些数据表明对过氧化氢的固有抗性和诱导抗性是菌株特异性的，并表明对于某些菌株，亚致死H2O2处理和细胞膜修饰可能有助于增加细胞对含益生菌食品的生产和储存过程中的氧化损伤的抗性。

著录项

  • 作者

    Oberg, Taylor.;

  • 作者单位

    Utah State University.;

  • 授予单位 Utah State University.;
  • 学科 Agriculture Food Science and Technology.;Biology Genetics.;Biology Microbiology.
  • 学位 Ph.D.
  • 年度 2013
  • 页码 191 p.
  • 总页数 191
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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