Changes of catalase(CAT) activities in the liver of Boleophthalmus pectinirostris with benzo(a)pyrene(BaP) exposure are detected in experimental condition. The results show that there is no significant changes for CAT activities in control group and 0.05mg·L -1 BaP group with prolonged exposure ( P >0.05), whereas they are depressed significantly at concentration of 0.5mg·L -1 ( P ≤0.05). In 3 days exposure, CAT activities decrease significantly with the increase of BaP concentration ( P ≤0.05). This might indicate that exposure to higher BaP concentrations might have toxic effect to fishes. The activities of CAT increase significantly to control level after BaP was removed. It turned out that the physiological modulatary mechanism still existed in the liver of Boleophthalmus pectinirostris . All the results show that CAT activity might be suitable to be the bioindicator of BaP exposure.
A spin-labeling fluorophore(NA-TEMPO ·), formed by labeling α-naphthalene with a paramagnetic nitroxide(4-hydroxyl-2,2,6,6-tetramethylpiperidinyl-1-oxy), was explored for biologically relevant carbon-centered radicals. The horseradish peroxidase (HPR)/H 2O 2 reaction was used to generate radicals in derivatives of tyrosine and phenylalanine, and the Fenton reaction was used to generate radicals in deoxyguanosine, guanosine, bovine serum albumin(BSA) and DNA. TEMPO ·-NA, a weak fluorescent compound, showed a dramatic increase in fluorescence intensity after scavenging carbon-centered radicals. The spin-labeling fluorophore with dual function groups, the radical recognizing group and fluorescent group, would be significantly useful in monitoring the formation and translocation of carbon-centered radicals in complex biological systems.
