HR: 0800h
AN: B21A-0858    [Abstracts]
TI: Aquifer Microbial Diversity Represented by Whole Cell and Dissolved DNA
AU: * Shields, M S
EM: shiemalc@isu.edu
AF: Department of Biological Sciences, Idaho State University, Pocatello, ID 83209-8007 United States
AU: Briggs, B
AF: Department of Biological Sciences, Idaho State University, Pocatello, ID 83209-8007 United States
AB: Microbial diversity measurements of aquifers are faced with two major sources of bias. These are a reflection of molecular (caused by amplification, labeling and extraction dissimilarities) and sampling aspects. Sampling of aquifers represents a considerable and often insurmountable bias since almost all evaluations rely on water samples where free living bacteria will predominate. This highly problematic when one desires to know the metagenomic potential of zone of well influence. We present a method designed to avoid cellular collection biases imposed by the difficulty in collecting attached biomass. Dissolved DNA (d-DNA) and whole bacterial cells were concentrated from Snake River Plain aquifer water. 96% of dDNA was recovered from DNA spiked surrogates using an anion-exchange membrane method. Approximately 2,000 ng DNA was recovered per liter of water. Total DNA turnover rate was measured at 49.3 ng/ml/day, at DNA concentrations above 1 mg/l, indicating that aquifer dDNA represents a dynamic steady state balanced between dDNA release and native DNA degradation activities. 16s, dual labeled T-RFLP analysis was used analyze the genomic complexity of whole bacterial cells collected via filtration versus d-DNA sources of bacterial DNA from 16 l of water. Highly similar T-RFLP profiles (with two restriction endonucleases) were obtained for both dDNA (200 nm filtrate) and the whole cells harvested from the same filter. This demonstrates that dDNA was an accurate reflection of the total bacterial community found within the well volume. We present evaluations of the anion-exchange system with respect to DNA recovery parameters, and demonstrate the suitability of this DNA template for PCR amplification reactions.
DE: 4805 Biogeochemical cycles (1615)
DE: 4803 Bacteria
DE: 1899 General or miscellaneous
DE: 1832 Groundwater transport
DE: 0400 Biogeosciences
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting