LAUSR

Abstract The world-wide application of cyclodiene pesticides (CP) lead to severe pollution of arable land and because of the long half-lives they will be for many decades present in the soil. The only reasonable way of the elimination of these chemicals from the soil is bioremediation – the introduction to the soil of decomposer microorganisms strains capable of CP degradation. CP are highly hydrophobic and exhibit large membrane activity; thus, they can be incorporated to the cellular membrane and retained therein. The presence of CP and their metabolites in the cellular membrane of the decomposer organism can lead to severe alterations of its function and in consequence to the death of the decomposer cell. Microorganisms protect themselves changing the phospholipid composition of their membranes. To shed light on the correlation between the membrane composition and its interactions with CP and their metabolites we applied Langmuir monolayers as versatile models of decomposers’ membranes. By the proper selection of phospholipids we prepared different models of cellular membranes of Gram-negative and Gram-positive bacteria. The model membranes were doped by four most frequently applied CP and their common metabolite. The combined application of microscopic, diffractometric and spectroscopic methods proved that CP can be incorporated into the model membranes and that the membrane activity of endosulfan is comparable with endrin – one of the most toxic pesticides. The penetration tests and spectroscopic studies proved also the possibility of the uptake of the polar CP metabolites by the model membranes from the aqueous subphase.