HR: 0800h
AN: B31A-0969    [Abstracts]
TI: Effect of Trichloroethylene on Minimum Energy Requirement and Gene Expression in a Nutrient Limited Methanotroph
AU: * Colwell, F S
EM: frederick.colwell@inl.gov
AF: Biological Sciences, Idaho National Laboratory, Idaho Falls, ID 83415-2203 United States
AU: Delwiche, M
EM: mark.delwiche@inl.gov
AF: Biological Sciences, Idaho National Laboratory, Idaho Falls, ID 83415-2203 United States
AU: Newby, D
EM: deborah.newby@inl.gov
AF: Biological Sciences, Idaho National Laboratory, Idaho Falls, ID 83415-2203 United States
AU: Wood, A
EM: alk44@nm.byu.edu
AF: Biology Department, Brigham Young University, Provo, UT 84601 United States
AU: Bingham, M
EM: bingmarie@isu.edu
AF: Biology Department, Idaho State University, Pocatello, ID 83201 United States
AU: Crawford, R L
EM: crawford@uidaho.edu
AF: Environmental Biotechnology Institute, University of Idaho, Moscow, ID 83844-1052 United States
AU: Strap, J L
EM: jstrap@uidaho.edu
AF: Environmental Biotechnology Institute, University of Idaho, Moscow, ID 83844-1052 United States
AB: Monitored natural attenuation (MNA) of contaminant plumes requires data for predictive modeling of plume destruction including the rates of microbial contaminant degradation. Methanotrophs are implicated in co-metabolism of trichloroethylene (TCE) in the Snake River Plain aquifer (SRPA) where MNA is the selected method of treatment. Our research aims to: 1) determine realistic activities of these cells when starved, a condition typical of subsurface microbes, and 2) detect the genes that are transcribed when methanotrophs experience stress or starvation related to TCE exposure and conditions in the subsurface. Methylosinus trichosporium OB3b (OB3b), a model methanotroph, was starved in a biomass recycle reactor and soluble methane monooxygenase (sMMO) activities determined, with and without TCE exposure (ca. 100 μg TCE/L). Starved methanotrophs, present at 3 x 10⁹ cells/mL in the reactor, consumed methane at 0.001 fmoles of methane/cell/day and gradually increased sMMO activities when exposed to higher methane concentrations. sMMO activities of starved OB3b cells exposed to TCE were indistinguishable from cells that were not exposed over brief (one day) periods. The sequences of eight genes, known to code for starvation/stress proteins, were retrieved from phylogenetic relatives (α-proteobacteria) of OB3b. Primers (18-22 bp) were designed from conserved regions in the consensus sequences to obtain OB3b-specific sequences for the eight genes. Primers for the starvation/stress genes successfully amplified all eight genes in OB3b using PCR. Our plan is to clone and sequence these OB3b genes then synthesize oligonucleotides that can be added to a microarray that includes targets for OB3b structural and regulatory gene sequences as a prelude to evaluating gene expression under different nutrient availability conditions and in the presence and absence of TCE. Incorporation of starvation-based rate estimates into natural attenuation models of contaminant plumes will permit estimates of the fraction of TCE natural attenuation that can be attributed to methanotrophic co-metabolism in a given aquifer system.
DE: 0418 Bioremediation
DE: 0448 Geomicrobiology
DE: 0465 Microbiology: ecology, physiology and genomics (4840)
SC: Biogeosciences [B]
MN: Fall Meeting 2005