Journal of Microbiology

Cloning of the Gene Responsible for Dechlorination of 4-Chlorobenzoate from Pseudomonas sp. DJ-12: Chae, Jong Chan , Kim, Young Chang , Kim, Young Soo , Kim, Chi Kyung; J. Microbiol. 1995;33(1):34-39.

Abstract: The gene responsible for dechlorination of 4-chlorobenzoate(4CBA) was cloned from chromosomal DNA of Pseudomonas sp. DJ-12 in Escherichia coli XL1-Blue by using pBluescript SK(+) phagemid vector. Two recombinant plasmids of pCJ1 and pCJ2 carrying dechlorinase gene were constructed. The inserted DNAs in the pCJ1 and pCJ2 were found to have the fragment of 9.5 kb carrying dechlorinase gene, but they were oriented in opposite direction. The inserted DNA of 3.4kb in the pCJ101 subclone carrying dechlorinase gene had two restriction sites for AccI and each one site for HincII, KpnI, PstI, and SacIi but the dechlorinase gene in pCJ101 was found to be placed over the HincII site. The dechlorinase fenes in the recombinant cells of E. coli CJ1 and CJ101 were well expressed to show the dechlorination activity of 4CBA. The proteins encoded by dechlorinase genes in E. coli CJ1 and CJ101 were about 49 kDa in molecular weight. But this protein was not produced by E. coli CJ102, CJ103 and E. coli XL1-Blue. Therefore, the proteins produced by Pseudomonas sp. DJ-12 and the cloned cells of E. coli CJ1 and CJ101 were thought to be the dechlorinase enzyme which was the product of dechlorinase gene.

Dechlorination of 4-Chlorobenzoate by Pseudomonas sp. DJ-12: Chae, Jong Chan , Kim, Chi Kyung; J. Microbiol. 1997;35(4):290-294.

Abstract: 4-Chlorobiphenyl-degrading Pseudomonas sp. DJ-12 was able to degrade 4-chlorobenzoate(4CBA), 4-iodobenzoate, and 4-bromobenzoate completely under aerobic conditions. During. the degradation of 4CBA by Pseudomonas sp. DJ-12, chloride ions were released by dechlorination and 4-hydroxybenzoate was produced as an intermediate metabolite. The NotI-KNA fragments of pKC157 containing dechlorination genes hybridized with the gene encoding 4CBA:CoA dehalogenase of Pseudomonas sp. CBS3 which is responsible for the hydrolytic dechlorination of 4CBA. These results imply that Pseudomonas sp. DJ-12 degrades 4CBA to 40hydroxybenzoate via dechlorination as the initial step of its degradativ pathway. The genes responsible for dechlorination of 4CBA were found to be blcated on the chromosomal DNA of Pseudomonas sp. DJ-12.

Production of Stress-shock Proteins in Pseudomonas sp. DJ-12 Treated with 4-Hydroxybenzoate: Park, Sang Ho , Oh, Kye Heon , Lee, Kil Jae , Kim, Chi Kyung; J. Microbiol. 1998;36(4):273-279.

Abstract: Pseudomonas sp. DJ-12 can grow on 4-hydroxybenzoate (4HBA) at concentration of 5 mM or lower by degrading 4HBA for carbon and energy sources. The organisms were found to produce DnaK stress-shock protein when treated with several aromatic hydrocarbons including 4HBA. Those cells treated with 5 mM 4HBA exhibited increased tolerance to 10 mM concentration. In this study, the production of other stress-shock kproteins besides KnaK was examined in Pseudomonas sp. DJ-12 exposed to various concentrations of 4HBA, compraing the production of the proteins with their survival and degradation of 4HBA. The organisms could degrade 4HBA at 0.5 to 5 mM concentrations after 60 to 90 minutes of incubation. The survival rate of the organism decreased when treated with 4HBA at 10 mM or higher concentrations. The stress-shock proteins of DnaK, GroEL, and GroES were produced in the cells which were treated with 4HBA at 0.5 mM or higher concentrations for 10 minutes. Fifteen additional stress-shock proteins were produced in the cells which were treated with 5 mM 4HBA for 40 minutes. The DnaK and GroEL proteins in the cells gradually decreased upto 6 hours after the stress was removed from the culture.

Catabolism of 4-Hydroxybenzoic Acid by Pseudomonas sp. DJ-12: Karegoudar, Timmanagouda B. , Chae, Jong Chan , Kim, Chi Kyung; J. Microbiol. 1999;37(3):123-127.

Abstract: A Pseudomonas sp. strain DJ-12 isolated by 4-cholrobiphenyl enrichment culture technique is capable of utilizing 4-hydroxybenzoic acid as a sole source of carbon and energy. The bacterium catabolized 4-hydroxybenzoic acid through the intermediate formation of protocatechuic acid, which was further metabolized. The cell free extracts of pseudomonas sp. DJ-12, grown on 4-hydroxybenzoic acid showed higher activities of 4-hydroxyenzoate 3-hydroxylase and protocatechuate 4,5-dioxygenase, but the activity of catechol 2,3-dioxygenase was lower. The results suggest that 4-hydroxybenzoic acid is catabolized via protocatechuic acid rather than catechol or gentisic acid in this bacterium and that the protocatechuic acid formed was metabolized through a metacleavage pathway by protocatechuate 4,5-dioxygenase.

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