title: Potential ecological risks of thermal-treated waste recombination DNA discharged into an aquatic environment.
abstract: It has been shown that thermal-treatment at 100 ° C can denature deoxyribonucleic acid (DNA), yet this does not cause it to break down completely. To clarify the risk of gene pollution from thermal-treated recombinant DNA, the renaturation characteristics of thermal-denatured plasmid pET-28b and its persistence in aquatic environments were investigated. The results revealed that the double-stranded structure and transforming activity of the thermal-treated plasmid DNA could be recovered even if the thermal-treatment was conducted at 120 ° C. The presence of sodium chloride (NaCl) and ethylenediamine tetraacetic acid (EDTA) led to the increase of renaturation efficiency of the denatured DNA. When thermal-treated plasmid DNA was discharged into simulated aquatic environments with pH values from 5 to 9, it showed a longer persistence at pH 7 and 8 than that at 5, 6 and 9; however, the denatured plasmid DNA could persist for more than 33 min at any pH. Moreover, a higher ionic strength further protected the thermal-denatured plasmids from degradation in the simulated aquatic environment. These results indicated that when the thermal-treated DNA was discharged into an aquatic environment, it might not break down completely in a short period. Therefore, there is the potential for the discarded DNA to renature and transform, which might result in gene pollution.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai, PR China.
authors.forename: Xiao H
authors.initials: XH
authors.lastname: Fu
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.forename: Meng N
authors.initials: MN
authors.lastname: Li
authors.forename: Xiao F
authors.initials: XF
authors.lastname: Zeng
authors.forename: Yi Q
authors.initials: YQ
authors.lastname: Le
mesh_terms: D004247:DNA / Q000737:chemistry*; D004492:Edetic Acid / Q000737:chemistry; D004777:Environment; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D009691:Nucleic Acid Denaturation; D009695:Nucleic Acid Renaturation; D010957:Plasmids / Q000737:chemistry*; D016133:Polymerase Chain Reaction; D012965:Sodium Chloride / Q000737:chemistry; D014873:Water Pollutants / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D014873:Water Pollutants; D012965:Sodium Chloride; D004247:DNA; D004492:Edetic Acid