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首页> 外文学位 >Interactions of bacteria and viruses with membranes and nanoparticles: Characterization of extracellular polymeric substances and photoinactivation of bacteriophages by fullerol nanoparticles.
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Interactions of bacteria and viruses with membranes and nanoparticles: Characterization of extracellular polymeric substances and photoinactivation of bacteriophages by fullerol nanoparticles.

机译：细菌和病毒与膜和纳米颗粒的相互作用：富勒醇纳米颗粒对细胞外聚合物的表征和噬菌体的光灭活。

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摘要

The extracellular polymeric substances produced by suspended cultures of Escherichia coli, Serratia marcescens, and Brevundimonas diminuta in the presence and absence of bismuth thiols and by activated sludge microorganisms in the presence of glucose were characterized in detail using colorimetric, spectroscopic, and microscopic techniques. 2:1 molar ratio preparations of three lipophilic bismuth thiols (BisBAL, BisEDT, and BisPYR) were investigated and BisBAL was found to be most effective for EPS suppression. Extensive homology between EPS samples in the presence and absence of bismuth was observed with proteins, carbohydrates and nucleic acids varying predominantly only in total amounts expressed. Fourier transform infrared spectroscopy (FTIR) suggested that a possible mechanism of biofilm disruption by BisBAL is the inhibition of carbohydrate O-acetylation and changes in protein secondary structures. Results suggest that antifouling properties of bismuth thiols originate in their ability to suppress O-acetylation, protein secondary structure formation, and free and bound EPS secretion. Bioflocculation appears to be inhibited through electrostatic repulsions when EPS content was low but was enhanced via polymeric interactions at high EPS concentrations. More specifically, microorganisms appeared to aggregate by producing protein secondary structures including aggregated strands, beta-sheets, alpha- and 3-turn helical structures, O-acetylated carbohydrates, as well as overall C--(0,N) and O=C--OH + O=C--OR functionalities.;Production of reactive oxygen species through photosensitization of polyhydroxylated fullerene (fullerol) is shown to enhance viral inactivation rates. The first-order MS2 bacteriophage inactivation rate nearly doubled due to the presence of 102, and increased by 125% due to 102 and superoxide when compared with UV-A illumination alone. When fullerol and NADH were present in solution, dark inactivation of viruses occurred at nearly the same rate as that produced by UV-A illumination without nanoparticles. Mechanisms of loss of virus infectivity were also probed using dsDNA bacteriophages with capsids of different composition (T7 and PRD1). The first order inactivation rate of phages in the presence of UV-A illuminated fullerol suspensions varied as MS2 > T7 > PRDI indicating the role of capsid composition in the susceptibility of viruses to singlet oxygen. Damage to T7 and PRD1 capsid proteins was identified using FTIR and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). SDS-PAGE analysis revealed the 1O2 induced alterations in capsid proteins such as oxidative cross-linking.
机译：使用比色法，分光镜和显微镜技术详细表征了在存在和不存在铋硫醇的条件下，由大肠杆菌，粘质沙雷氏菌和短小Brevundimonas diminuta的悬浮培养物产生的细胞外聚合物质，以及在葡萄糖存在下由活性污泥微生物产生的细胞外聚合物。对三种亲脂性铋硫醇（BisBAL，BisEDT和BisPYR）的摩尔比为2：1的制剂进行了研究，发现BisBAL对于抑制EPS最有效。观察到在存在和不存在铋的情况下EPS样品之间的广泛同源性，其中蛋白质，碳水化合物和核酸的主要变化仅在于表达的总量。傅里叶变换红外光谱（FTIR）表明BisBAL破坏生物膜的可能机制是抑制碳水化合物的O-乙酰化和蛋白质二级结构的改变。结果表明，铋硫醇的防污特性源自其抑制O-乙酰化，蛋白质二级结构形成以及游离和结合的EPS分泌的能力。当EPS含量低时，生物絮凝似乎受到静电排斥的抑制，但在高EPS浓度下通过聚合物相互作用而增强。更具体地说，微生物似乎通过产生蛋白质二级结构而聚集，这些二级结构包括聚集的链，β-折叠，α和3匝螺旋结构，O-乙酰化碳水化合物以及总的C-（0，N）和O = C -OH + O = C-OR官能度；通过多羟基化富勒烯（富勒醇）的光敏化生产活性氧物种显示可提高病毒的灭活率。与单独的UV-A照射相比，由于存在102，一阶MS2噬菌体失活率几乎翻倍，并且由于102和超氧化物而增加了125％。当溶液中存在富勒醇和NADH时，病毒的暗灭活率几乎与没有纳米粒子的UV-A照射产生的速率相同。还使用具有不同组成（T7和PRD1）的衣壳的dsDNA噬菌体检测了病毒感染力丧失的机制。在存在UV-A照射的富勒醇悬浮液的情况下，噬菌体的一级失活速率随MS2> T7> PRDI的变化而变化，表明衣壳组成在病毒对单线态氧的敏感性中的作用。使用FTIR和十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）鉴定了对T7和PRD1衣壳蛋白的损伤。 SDS-PAGE分析揭示了衣壳蛋白中1O2诱导的改变，例如氧化交联。

著录项

  • 作者

    Badireddy, Appala Raju.;

  • 作者单位

    University of Houston.;

  • 授予单位 University of Houston.;
  • 学科 Health Sciences Toxicology.;Engineering Environmental.;Chemistry Biochemistry.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 131 p.
  • 总页数 131
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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