Environmental Whole-Genome Amplification to Access Microbial Diversity in Contaminated Sediments
Low-biomass samples from nitrate and heavy metal contaminated soils yield DNA amounts that have limited use for direct, native analysis and screening. Multiple displacement amplification (MDA) using ?29 DNA polymerase was used to amplify whole genomes from environmental, contaminated, subsurface sediments. By first amplifying the genomic DNA (gDNA), biodiversity analysis and gDNA library construction of microbes found in contaminated soils were made possible. The MDA method was validated by analyzing amplified genome coverage from approximately five Escherichia coli cells, resulting in 99.2 percent genome coverage. The method was further validated by confirming overall representative species coverage and also an amplification bias when amplifying from a mix of eight known bacterial strains. We extracted DNA from samples with extremely low cell densities from a U.S. Department of Energy contaminated site. After amplification, small subunit rRNA analysis revealed relatively even distribution of species across several major phyla. Clone libraries were constructed from the amplified gDNA, and a small subset of clones was used for shotgun sequencing. BLAST analysis of the library clone sequences showed that 64.9 percent of the sequences had significant similarities to known proteins, and ''clusters of orthologous groups'' (COG) analysis revealed that more than half of the sequences from each library contained sequence similarity to known proteins. The libraries can be readily screened for native genes or any target of interest. Whole-genome amplification of metagenomic DNA from very minute microbial sources, while introducing an amplification bias, will allow access to genomic information that was not previously accessible.
- Research Organization:
- COLLABORATION - Collaboration with Diversa,SanDiego, California; Oak Ridge National Laboratory; and Virtual Institutefor Microbial Stress and Survival
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC02-05CH11231
- OSTI ID:
- 894235
- Report Number(s):
- LBNL--60416
- Journal Information:
- Applied and Environmental Microbiology, Journal Name: Applied and Environmental Microbiology Journal Issue: 5 Vol. 72; ISSN AEMIDF; ISSN 0099-2240
- Country of Publication:
- United States
- Language:
- English
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