Lehman R Michael, O'Connell Seán P
Idaho National Engineering and Environmental Laboratory, Biotechnologies Department, Idaho Falls, Idaho 83415-2203, USA.
Appl Environ Microbiol. 2002 Apr;68(4):1569-75. doi: 10.1128/AEM.68.4.1569-1575.2002.
Free-living and surface-associated microbial communities in sand-packed columns perfused with groundwater were compared by examination of compositional and functional characteristics. The composition of the microbial communities was assessed by bulk DNA extraction, PCR amplification of 16S ribosomal DNA fragments, separation of these fragments by denaturing gradient gel electrophoresis, and sequence analysis. Community function was assessed by measurement of beta-glucosidase and aminopeptidase extracellular enzyme activities. Free-living populations in the aqueous phase exhibited a greater diversity of phylotypes than populations associated with the solid phase. The attached bacterial community displayed significantly greater beta-glucosidase and aminopeptidase enzyme activities per volume of porous medium than those of the free-living community. On a per-cell basis, the attached community had a significantly higher cell-specific aminopeptidase enzyme activity (1.07 x 10(-7) nmol cell(-1) h(-1)) than the free-living community (5.02 x 10(-8) nmol cell(-1) h(-1)). Conversely, the free-living community had a significantly higher cell-specific beta-glucosidase activity (1.92 x 10(-6) nmol cell(-1) h(-1)) than the surface-associated community (6.08 x 10(-7) nmol cell(-1) h(-1)). The compositional and functional differences observed between these two communities may reflect different roles for these distinct but interacting communities in the decomposition of natural organic matter or biodegradation of xenobiotics in aquifers.
通过对组成和功能特征的检测，比较了在灌注地下水的填砂柱中自由生活和与表面相关的微生物群落。通过大量DNA提取、16S核糖体DNA片段的PCR扩增、变性梯度凝胶电泳分离这些片段以及序列分析来评估微生物群落的组成。通过测量β-葡萄糖苷酶和氨肽酶的细胞外酶活性来评估群落功能。水相中的自由生活种群比与固相相关的种群表现出更多样化的系统发育型。每体积多孔介质中，附着的细菌群落显示出比自由生活群落显著更高的β-葡萄糖苷酶和氨肽酶活性。以每细胞为基础，附着群落的细胞特异性氨肽酶活性（1.07×10⁻⁷ nmol细胞⁻¹ h⁻¹）显著高于自由生活群落（5.02×10⁻⁸ nmol细胞⁻¹ h⁻¹）。相反，自由生活群落的细胞特异性β-葡萄糖苷酶活性（1.92×10⁻⁶ nmol细胞⁻¹ h⁻¹）显著高于与表面相关的群落（6.08×10⁻⁷ nmol细胞⁻¹ h⁻¹）。在这两个群落之间观察到的组成和功能差异可能反映了这些不同但相互作用的群落在含水层中天然有机物分解或外源化合物生物降解中的不同作用。
