Adsorption of plasmid DNA to mineral surfaces and protection against DNase I

Journal Article · Mon Apr 01 00:00:00 EST 1991 · Applied and Environmental Microbiology; (United States)

OSTI ID:5535328

Romanowski, G; Lorenz, M G; Wackernagel, W ^[1]

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1. Univ. Oldenburg (West Germany)

The adsorption of ({sup 3}H)thymidine-labeled plasmid DNA (pHC314; 2.4 kb) of different conformations to chemically pure sand was studied in a flowthrough microenvironment. The extent of adsorption was affected by the concentration and valency of cations, indicating a charge-dependent process. Bivalent cations (Mg{sup 2+}, Ca{sup 2+}) were 100-fold more effective than monovalent cations (Na{sup +}, K{sup +}, NH{sub 4}{sup +}). Quantitative adsorption of up to 1 {mu}g of negatively supercoiled or linearized plasmid DNA to 0.7 g of sand was observed in the presence of 5 mm MgCl{sub 2} at pH 7. Under these conditions, more than 85% of DNA adsorbed within 60 s. Maximum adsorption was 4 {mu}g of DNA to 0.7 g of sand. Supercoil molecules adsorbed slightly less than linearized or open circular plasmids. An increase of the pH from 5 to 9 decreased adsorption at 0.5 mM MgCl{sub 2} about eightfold. It is concluded that adsorption of plasmid DNA to sand depends on the neutralization of negative charges on the DNA molecules and the mineral surfaces by cations. The results are discussed on the grounds of the polyelectrolyte adsorption model. Sand-adsorbed DNA was 100 times more resistant against DNase I than was DNA free in solution. The data support the idea that plasmid DNA can enter the extracellular bacterial gene pool which is located at mineral surfaces in natural bacterial habitats.

• OSTI ID: 5535328
• Journal Information: Applied and Environmental Microbiology; (United States), Vol. 57:4; ISSN 0099-2240
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
RECOMBINANT DNA
ENVIRONMENTAL TRANSPORT
ADSORPTION
DNA-ASE
GENETIC ENGINEERING
MINERALS
PLASMIDS
SOILS
THYMIDINE
TRACER TECHNIQUES
TRITIUM COMPOUNDS
AZINES
BIOTECHNOLOGY
CELL CONSTITUENTS
DNA
ENZYMES
ESTERASES
HETEROCYCLIC COMPOUNDS
HYDROGEN COMPOUNDS
HYDROLASES
ISOTOPE APPLICATIONS
MASS TRANSFER
NUCLEIC ACIDS
NUCLEOSIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOSPHODIESTERASES
PROTEINS
PYRIMIDINES
RIBOSIDES
SORPTION
540211* - Environment
Terrestrial- Basic Studies- Radiometric Techniques- (1990-)