Hilyard Edward J, Jones-Meehan Joanne M, Spargo Barry J, Hill Russell T
Naval Research Laboratory, Washington, DC 20375, USA.
Appl Environ Microbiol. 2008 Feb;74(4):1176-82. doi: 10.1128/AEM.01518-07. Epub 2007 Dec 21.
The diversity of indigenous bacteria in sediments from several sites in the Elizabeth River (Virginia) able to degrade multiple polycyclic aromatic hydrocarbons (PAHs) was investigated by the use of classical selective enrichment and molecular analyses. Enrichment cultures containing naphthalene, phenanthrene, fluoranthene, or pyrene as a sole carbon and energy source were monitored by denaturing gradient gel electrophoresis (DGGE) to detect changes in the bacterial-community profile during enrichment and to determine whether the representative strains present were successfully cultured. The DGGE profiles of the final enrichments grown solely on naphthalene and pyrene showed no clear relationship with the site from which the inoculum was obtained. The enrichments grown solely on pyrene for two sample sites had >80% similarity, which suggests that common pyrene-degrading strains may be present in these sediments. The final enrichments grown on fluoranthene and phenanthrene remained diverse by site, suggesting that these strains may be influenced by environmental conditions. One hundred and one isolates were obtained, comprising representatives of the actinomycetes and alpha-, beta-, and gammaproteobacteria, including seven novel isolates with 16S rRNA gene sequences less than 98% similar to known strains. The ability to degrade multiple PAHs was demonstrated by mineralization of 14C-labeled substrate and growth in pure culture. This supports our hypothesis that a high diversity of bacterial strains with the ability to degrade multiple PAHs can be confirmed by the combined use of classical selective enrichment and molecular analyses. This large collection of diverse PAH-degrading strains provides a valuable resource for studies on mechanisms of PAH degradation and bioremediation.
通过经典的选择性富集和分子分析方法，对弗吉尼亚州伊丽莎白河多个地点沉积物中能够降解多种多环芳烃（PAHs）的本土细菌多样性进行了研究。以萘、菲、荧蒽或芘作为唯一碳源和能源的富集培养物，通过变性梯度凝胶电泳（DGGE）进行监测，以检测富集过程中细菌群落谱的变化，并确定所存在的代表性菌株是否成功培养。仅以萘和芘为碳源生长的最终富集培养物的DGGE图谱与接种物来源的地点没有明显关系。两个采样点仅以芘为碳源生长的富集培养物相似度>80%，这表明这些沉积物中可能存在常见的芘降解菌株。以荧蒽和菲为碳源生长的最终富集培养物在不同地点仍具有多样性，表明这些菌株可能受环境条件影响。共获得101株分离菌，包括放线菌以及α-、β-和γ-变形菌的代表菌株，其中有7株新分离菌，其16S rRNA基因序列与已知菌株的相似度低于98%。通过14C标记底物的矿化作用和纯培养中的生长，证明了这些菌株具有降解多种PAHs的能力。这支持了我们的假设，即通过经典选择性富集和分子分析相结合，可以确认具有降解多种PAHs能力的细菌菌株具有高度多样性。这一大批多样的PAH降解菌株为PAH降解机制和生物修复研究提供了宝贵资源。
