Molecular Mechanisms of the Response to 4-tert-Octylphenol-Induced Stress in a Cyanobacterium Planktothrix agardhii

Resumo

The molecular mechanisms of stress response of Planktothrix agardhii, one of the dominant cya-nobacteria in the basins of the Northwestern Russia and other regions during “blooming,” on the effect of 4-tert-octylphenol (OP), a hormone-like xenobiotic of anthropogenic origin, were studied. In the presence of OP, an increase in the permeability of P. agardhii cell membranes occurred, one of the reasons for which was the oxidation of membrane lipids under conditions of oxidative stress caused by generation of reactive oxygen species. A dose-dependent increase of the activities of enzymatic and non-enzymatic antioxidants in P. agardhii was registered in response to octylphenol-induced oxidative stress, indicating OP action as an activator of expression of stress regulons genes. Due to the structural similarity of 4-tert-octylphenol and alkylresorcinols (AR), the natural microbial regulators controlling development of microbial populations, OP released into the environment may imitate the functions of AR, interfering with the communication process of microbial cells in the population, which may adversely affect the succession and stability of functioning of microbial communities.