Toxicokinetic and toxicodynamic symbiotic interactions among intestinal Pseudomonas degrading of hydrocarbons with its wild host fish Chirostoma jordani

The symbiotic relationship between native microbiota and their hosts probably is a key factor in animal survival. In this study, the relationships of Pseudomonas spp. strains with specific biomarkers of exposure to polycyclic aromatic hydrocarbons (PAHs) in wild fish Chirostoma jordani, as well as the capacity of these bacteria to biotransform PAHs were evaluated. The activity of the naphthalene dioxygenase system of the bacteria exposed to 0.1, 1.0 and 10 µg/L of PAHs was higher than the mean isoform 1A1 (CYP1A1) of the wild fish, particularly bacterial species related to Pseudomonas spp. However, the epoxide hydrolase activity of the strains was lower in all cases compared to the fish. Glutathione S-transferase (GST) activity of the bacterial strains was lower than in the liver, but higher than in viscera of C. jordani. Using redundancy analysis, two differential patterns were found: (i) CYP1A1 activity of fish was induced by naphthalene and anthracene water levels independently of sampling season and lakes monitored, and (ii) the unidentified strain of the Pseudomonas genus biotransforms the endogenous levels of benzo[a]pyrene, benzo[k]fluoranthene and indeno[1,2,3-cd]pyrene in the fish allowing the hydroxylated metabolites to conjugate with glutathione through GST activity of the fish.