title: Interactions between dissolved natural organic matter and adsorbed DNA and their effect on natural transformation of Azotobacter vinelandii.
abstract: To better understand gene transfer in the soil environment, the interactions between dissolved natural organic matter (NOM) and chromosomal or plasmid DNA adsorbed to silica surfaces were investigated. The rates of NOM adsorption onto silica surfaces coated with DNA were measured by quartz crystal microbalance (QCM) and showed a positive correlation with carboxylate group density for both soil and aquatic NOM in solutions containing either 1mM Ca(2+) or Mg(2+). Increasing total dissolved organic carbon (DOC) concentrations of the NOM solution also resulted in an increase in the adsorption rates, likely due to divalent cation complexation with NOM carboxylate groups and the phosphate backbones of the DNA. The results from Fourier transform infrared spectroscopy (FTIR) for dissolved DNA and DNA adsorbed on silica beads also suggest that adsorption may result from divalent cation complexation with the DNA's phosphate backbone. The interactions, between DNA and NOM, however, did not influence natural transformation of Azotobacter vinelandii by DNA. These results suggest that DNA adsorbed to NOM-coated silica or otherwise complexed with NOM remains available for natural transformation in the environment.
authors.affiliation: Department of Civil and Environmental Engineering, University of Illinois at Urbana Champaign, Urbana, IL 61801, USA.
authors.forename: Nanxi
authors.initials: N
authors.lastname: Lu
authors.forename: Steven E
authors.initials: SE
authors.lastname: Mylon
authors.forename: Rong
authors.initials: R
authors.lastname: Kong
authors.forename: Rohit
authors.initials: R
authors.lastname: Bhargava
authors.forename: Julie L
authors.initials: JL
authors.lastname: Zilles
authors.forename: Thanh H
authors.initials: TH
authors.lastname: Nguyen
mesh_terms: D000222:Adaptation, Physiological; D000327:Adsorption; D016948:Azotobacter vinelandii; D002118:Calcium / Q000737:chemistry / Q000378:metabolism; D002413:Cations, Divalent; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D004785:Environmental Pollutants / Q000737:chemistry / Q000378:metabolism; D022761:Gene Transfer, Horizontal; D006812:Humic Substances; D007700:Kinetics; D008274:Magnesium / Q000737:chemistry / Q000378:metabolism; D010710:Phosphates / Q000737:chemistry / Q000378:metabolism; D010957:Plasmids / Q000378:metabolism; D012822:Silicon Dioxide / Q000737:chemistry / Q000378:metabolism
chemical_list: D002413:Cations, Divalent; D004785:Environmental Pollutants; D006812:Humic Substances; D010710:Phosphates; D012822:Silicon Dioxide; D004247:DNA; D008274:Magnesium; D002118:Calcium