• Journal of Environmental Health Sciences
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• v.27 no.2
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• pp.10-16
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• 2001

To evaluate an effect of circadian variation on the xylene metabolizing enzyme activities, 50% m-xylene in olive oil(0.25 $m\ell$/100g body weight) was intraperitoneally administered to the rats every other day for 6 days both in the night; 24:00 and the day; 12:00. Then animals were sacrigiced at 8hr after last injection of m-xylene. Hepatic microsomal cytochrome p450 contents were more increased both in control and xylene treated rats of night phase than those of day phase. But the activity of hepatic alcohol dehydrogenase(ADH) in control of night phase showed the similar value with that in those of day phase and xylene treated rats of day phase showed an increasing tendency of hepatic ADH activity as those of night phase showing similar activity. Furthermore, control rats of night phase than those of day phase. And by xylene treatment, enzyme activities of rats of day phase were higher tendency in rats of control but those of night phase were somewhat inhibited. Besides, xylene-treated animals of night phase showed increasing tendency of urinary methylhippuric acid concentration compared with those of day phase. On the other hand, liver weight per body weight(%), hepatic lipid peroxide content and serum xanthine oxidase activity were higher in night phase. And the activities of hepatic oxygen free radical metabolizing enzymes such as xanthine oxidase, gluthathione S-transferase, and xylene-treated rats of night phase than those of day phase. In conclusion, it can be hypothesized on the basis of the results that the accumulation rate of m-xylene intermediate metabolite, i.e. m-methylbenzaldehyde in liver tissus may be higher in night phase than in day phase and it may be responsible for higher liver toxicity in bight phase than in day phase.

• Proceedings of the Korean Environmental Health Society Conference
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• 2001.04a
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• pp.119-119
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• 2001

• Biomedical Science Letters
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• v.8 no.2
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• pp.83-88
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• 2002

To investigate the skin toxicity of xylene, xylene (25 mg/$\textrm{cm}^2$) has been sequentially applied to the rat skin for four days. On the light microscopic examination, epithelium was left out with infiltration of inflammatory cells in border with dermis, and formation of new epithelial layer was shown under the inflammatory zone. Application of xylene to the rat skin showed the marked rise of cutaneous xanthine oxidase activity whereas, He activities of oxygen free radical scavenging enzymes, superoxide dismutase and glutathione S-transferase, were significantly declined. Furthermore, the content of cutaneous glutathione was more and less decreased in rat skin applied with xylene. In conclusion, these results suggest that a part of oxygen free radical may be responsible for morphological changes in skin by applying xylene to the rat skin.

• Toxicological Research
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• v.11 no.2
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• pp.205-213
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• 1995

This study was undertaken to investigate the effects of organic solvents on xenobiotic metabollzing enzyme system in vivo by meaas of experimental conditions i.e. (1) single group which was treated by benzene (B), toluene (T) and xylene (X), respectively, (2) combination group which was treated by mixture of benzene+toluene (BT), benzene+xylene (BX), and toluene+xylene (TX), respectively, (3) mixture group which was treated by benzene+ toluene+xylene mixture (M), and to interpreat the interaction between the organic solvents metabolizing enzymes. 1. The contents of cytochrome P-450 in liver microsomes were increased (p < 0.01) in organic solvents treated groups, and the contents of cytochrome P-450 were increased by following order of B < T < M < BT=BX < X < TX. 2. The activity of cytochrome P-450 dependent AHHase was significantly higher in organic solvents treated groups than in control group (p < 0.01), and the activity of AHHase was increased by following order of B < T < BT=BX=TX=xylene < M. 3. The activity of NADPH P-450 reductase was significantly higher in organic solvents treated groups than in control group (p < 0.01), and the order of M < combinated group < X < T

• Microbiology and Biotechnology Letters
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• v.17 no.2
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• pp.100-108
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• 1989

Thirty-six aromatic compound biodegraders; 10 strains for benzoate, 10 for salicylate, 6 for m-toluate, and 10 for DL-camphor were isolated and taxonomically characterized. A mutant Pseudomonas strain, Ben 6-2, derived from Ben 6 revealed remarkably improved ability to metabolize benzoate. Thus enhancement of the average substrate removal rate from 5.2 to 11.0mg/$\ell$/ hr was attained by the mutant. Both of strains Sal 7 and Tol 2, degraders of salicylate and m-toluate respectively, were classified as Pseudomonas sup. Both strains were found to be extremely effective in metabolizing each aromatic substrates. The average substrate degradation rates in minimal salt media containing 2,200mg/$\ell$ of the substrate were calculated to be 40.1 mg/$\ell$/ hr for strain Sal 7 and 33.0mg/$\ell$/ hr for Tol 2. Cam 10, a camphor degrading strain was demonstrated to be capable of mineralizing benzoate, phenol, toluene, octane, cyclohexane and xylene as well as camphor. Strain 1040 isolated from Cam 10 after repented adaptation to 1,000 mg/$\ell$ m-toluate gained the ability to utilize toluate as a sole carbon source. The mutant Brew actively at the expense of a mixture of car-bon sources; camphor, m-toluate, benzoate and phenol (each: 200 mg/$\ell$) and utilized the substances in the preferential order of camphor, phenol, benzoate, and m-toluate. Among the biodegraders examined Cam 1040 and Tol 2 were detected to harbor plasmid. The plasmid from Cam 1001 was determined to be about 98kb, and evidenced to encode the enzyme(s) for the degradation of camphor. For the further diversification of the metabolic potentials of Cam 1040, the NAH 2 plasmid of Pseudomonas putida NCIB 9816 was transferred to Cam 1040 by conjugation. The exconjugant obtained, Cam 1043, proved to gain an additional ability to metabolize salicylate and naphthalene.