Abstract

Pseudomonas sp. DJ-12 is capable of degrading biphenyl, 4-chlorobiphenyl (4CB), and 4-hydroxybenzoate (4HBA) at relatively low concentrations. The degradability and cellular responses of the organism to the aromatic pollutants at higher concentrations have not been studied. In this study, the survival of the cells, production of stress proteins, and induction of tolerance were examined by exposing cells to various concentrations of the aromatics. The survival rates of the organism were reversely proportional to the concentration of each aromatic during incubation for 6 hs. Stress protein specifically reacting with anti-DnaK monoclonal antibody was commonly produced when cells were treated with each aromatic. Those cells pretreated with each aromatic at lower concentrations exhibited a certain degree of tolerance to higher concentrations of the aromatics. Such cellular responses of the organism to water-soluble 4HBA were more clearly distinguished than those to insoluble 3CB and biphenyl. Therefor, induction of DnaK stress protein in the cells by exposure to the aromatiocs could be used to develop an indicator for pollution by the aromatics.

• Keywords: Aromatics stress; stress response; DnaK stress protein; western blot; Pseudomonas sp.DJ-12.