The Contribution of Soil Constituents to Adsorption of Extracellular DNA by Soils

Abstract

The adsorption of DNA by an andosol was much greater than that by a fluvisol or acrisol. The decrease in soil organic matter on treatment with hydrogen peroxide (H2O2) little affected DNA adsorption per weight of the particles, implying that the organic matter is not involved in the adsorption. The acid oxalate treatment of the H2O2-treated soils decreased DNA adsorption. Among soil constituents, acid oxalate-extractable materials such as allophane and noncrystalline Al and Fe oxides are likely to make a major contribution to the adsorption of DNA.

The Influence of Soil Organic Matter on DNA Adsorptions on Andosols

“…The adsorption maximum of the H2O2-treated TA soil, 4.71 mg g −1 was higher than that of the untreated soil, 3.19 mg g −1 , although surface area was greatly decreased by the treatment. Also, the decrease in organic matter content of KB soil little affected DNA adsorption per unit weight, in the H2O2-treated soil particles (19). Similarly, H 2 O 2 -treatment of a clay fraction of Alfisol increased significantly DNA adsorption (2).…”

“…This result was consistent with the finding that almost all DNA was extracted from the same MY+slurry soil in the study of microbial communities while much DNA could not be extracted from the untreated MY soil (Sakai, personal communication). * The data for Sample KB was quoted from our previous study (19). The effect of removing organic matter on DNA adsorption in the andosols The effects of soil organic matter on DNA adsorption in the soils were investigated by reducing the organic matter contents of the soils with H 2 O 2 treatment (Fig.…”

“…Some researchers have also considered that DNA molecules bind to OH groups on the edge of phyllosilicates such as montmorillonite (9,11,15). A previous study (19) indicated that oxide minerals in soils are one of the most important adsorbents for DNA molecules, because adsorption was lowered when Fe or Al oxides including allophane were removed from the H 2 O 2 -treated soil by an acid-oxalate Fig. 3c, where the DNA molecules associate with the surface of negatively charged materials such as phyllosilicates via a bridging of cations.…”

“…Second, these treatments form new adsorptive sites due to the appearance of Al and Fe oxides trapped in organic matter. Our previous study indicated that oxide minerals in soils are one of the most important adsorbents for DNA molecules (19). Consequently, DNA adsorption would depend on the qualitative conditions of the soil particle's surfaces rather than simply on the specific surface area of the particles.…”

“…In a previous study (19), DNA adsorption in soils was investigated using andosol, fluvisol, and acrisol samples taken in Japan. The andosol was found to adsorb much more DNA than the fluvisol or acrisol.…”