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(M/EH081) Studies of bacterial chemotaxis to polycyclic aromatic hydrocarbons. Marchenko, Anatolyi1, Zavalskyi, Leonid1, Ortega, Jose2, Dyaditschev, Nickolay1, Borovick, Roman1, 1 2 ABSTRACT- The low bioavailability of polycyclic aromatic hydrocarbons restricts the bioremediation of polluted soils. One of the mechanisms by which bacteria might improve their access to poor soluble chemicals is chemotaxis. Chemotaxis of bacteria-degraders of polycyclic aromatic hydrocarbons (Pseudomonas putida AZ, Pseudomonas fluorescens MZ-20, Azospirillum sp. SA-1) with respect to naphthalene, phenanthrene has been studied by the vertical densitometry method in chemoeffector gradient. Data have been analyzed using a kinetic model of bacterial chemotaxis and compared with the data obtained in parallel by other methods: capillary Adler`s method and forming chemotactic rings in semiliquid agar. Pseudomonas putida AZ and Azospirillum sp. SA-1 were attracted to naphthalene. Naphthalene and phenanthrene were shown to be attractants to P. fluorescens MZ-20, the naphthalene being the most potent and the phenanthrene the least. The chemotactic response of investigated microbial cultures to naphthalene and phenanthrene was dependent on induction by growth of microbial cells on these substances. The chemotactic response of P. fluorescens Mz-20 and Azospirillum sp. SA-1 to a variety of sterilized by filtration root exudates of plants. Azospirillum sp. SA-1 strain showd positive chemotaxis towads root exudates of the wheat, oats. P. fluorescens MZ-20 was attracted to root exudates of alfalfa, white clover, and meadow fescue. This demonstrated that soil bacteria have devised signaling system to monitor its chemical environment. Present observation might be importance for enhanced phytoremediation of PAHs polluted soils. The investigations have been perfomed under financial support of the ISTC, the project #1429. Key words: bioavailability, chemotaxis, PAH, phytoremediation |
