Effect of molecular characteristics of DNA on its adsorption and binding on homoionic montmorillonite and kaolinite

Citation
G. Pietramellara et al., Effect of molecular characteristics of DNA on its adsorption and binding on homoionic montmorillonite and kaolinite, BIOL FERT S, 33(5), 2001, pp. 402-409
Citations number
28
Categorie Soggetti
Environment/Ecology
Journal title
BIOLOGY AND FERTILITY OF SOILS
ISSN journal
01782762 → ACNP
Volume
33
Issue
5
Year of publication
2001
Pages
402 - 409
Database
ISI
SICI code
0178-2762(200105)33:5<402:EOMCOD>2.0.ZU;2-7
Abstract
Adsorption or binding of DNA by montmorillonite or kaolinite, homoionic to Ca2+, was not affected by base composition, blunt or cohesive ends. Fitting data to both Freundlich and Langmuir adsorption isotherms showed that the amount of lower molecular mass DNA adsorbed and bound by both clay minerals was higher than that of the higher molecular mass DNA. The relevance of ph osphate groups for the adsorption of DNA by clay minerals was investigated by adding sodium metaphosphate before and after the addition of DNA to clay minerals: DNA was partially not adsorbed even at low concentrations of sod ium metaphosphate. The fact that the observed DNA was partially desorbed by washing with double-distilled H2O indicated that bonds with different degr ees of strength were formed between DNA molecules and clay minerals. The hi gher molecular mass DNA could interact with a larger number of binding site s on the external surface of clay mineral than the lower molecular mass DNA . The number of external surface binding sites was higher on kaolinite than on montmorillonite.