• Environmental Engineering Research
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• v.7 no.2
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• pp.85-92
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• 2002

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2001.06a
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• pp.114-115
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• 2001

• Proceedings of the Microbiological Society of Korea Conference
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• 1999.04a
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• pp.52.1-52.1
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• 1999

• Molecules and Cells
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• v.21 no.2
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• pp.218-223
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• 2006

The effect of poly(ADP-ribosyl)ation on the stability of p53 in SK-HEP1 cells treated with UV light was examined. Intracellular levels of p53 increased in cells treated with a low dose of UV light ($20J/m^2$), whereas they increased but then declined after a higher dose of UV ($100J/m^2$). Intracellular levels of p53 in the UV treated SK-HEP1 cells were dependent on the UV dose. Use of proteasome inhibitors revealed that p53 is degraded by proteasomal proteolysis after high doses of UV light. We present evidence that, at low doses, poly(ADP-ribose)polymerase (PARP) poly(ADP-ribosyl) ates p53 and protects it from proteasomal degradation before caspase-3 is activated, whereas at high doses the cells undergo UV induced apoptosis and PARP is cleaved by caspase-3 before it can protect p53 from degradation. Destabilization of p53 by cleavage of PARP may be important in cell fate decision favoring apoptosis.

• Animal cells and systems
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• v.16 no.3
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• pp.173-182
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• 2012

The p53 protein plays a pivotal role in tumor suppression. The cellular level of p53 is normally kept low by proteasome-mediated degradation, allowing cell cycle progression and cell proliferation. Under stress conditions, such as DNA damage, p53 is stabilized and activated through various post-translational modifications of itself as well as of its regulatory proteins for induction of the downstream genes responsible for cell cycle arrest, DNA repair, and apoptosis. Therefore, the level of p53 should be tightly regulated for normal cell growth and for prevention of the accumulation of mutations in DNA under stress conditions, which otherwise would lead to tumorigenesis. Since the discovery of Mdm2, a critical ubiquitin E3 ligase that destabilizes p53 in mammalian cells, nearly 20 different E3 ligases have been identified and shown to function in the control of stability, nuclear export, translocation to chromatin or nuclear foci, and oligomerization of p53. So far, a large number of excellent reviews have been published on the control of p53 function in various aspects. Therefore, this review will focus only on mammalian ubiquitin E3 ligases that mediate proteasome-dependent degradation of p53.

• Journal of Applied Biological Chemistry
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• v.59 no.1
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• pp.9-12
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• 2016

Strain AP01 was isolated for the biological cypermethrin degradation from soil and sediment in Busan. This strain was identified on the basis of phylogenetic analysis of the 16s rDNA sequence and assigned as Bacillus amyloliquefaciens AP01. AP01 could degrade about 45% of cypermethrin in the mineral medium at $30^{\circ}C$ and 180 rpm for 5 days. Furthermore when 2% glucose was added in the medium, the degradation rate of cypermethrin by strain AP01 was increased upto about 60%. Therefore, AP01 may serve as a promising strain in the bioremediation of soil polluted with cypermethrin.

• Macromolecular Research
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• v.15 no.4
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• pp.363-369
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• 2007

Novel biodegradable elastic hydrogels, based on hydrophilic and hydrophobic polymer blocks, were synthesized via the radical crosslinking reaction of diacrylates of poly(ethylene glycol) (PEG) and poly(${\varepsilon}-caprolactone$) (PCL). PEG and PCL diols were diacrylated with acryloyl chloride in the presence of triethylamine, with the reaction confirmed by FT-IR and $^1H-NMR$ measurements. The diacrylate polymers were used as building-blocks for the syntheses of a series of hydro gels, with different block compositions, by simply varying the feed ratios and molecular weights of the block components. The swelling ratio of the hydrogels was controlled by the balance between the hydrophilic and hydrophobic polymer blocks. Usually, the swelling ratio increases with increasing PEG content and decreasing block length within the network structure. The hydrogels exhibited negative thermo-sensitive swelling behavior due to the coexistence of hydrophilic and hydrophobic polymer components in their network structure, and such thermo-responsive swelling/deswelling behavior could be repeated using a temperature cycle, without any significant change in the swelling ratio. In vitro degradation tests showed that degradation occurred over a 3 to 8 month period. Due to their biodegradability, biocompatibility, elasticity and functionality, these hydrogels could be utilized in various biomedical applications, such as tissue engineering and drug delivery systems.

• Journal of Life Science
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• v.28 no.4
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• pp.483-487
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• 2018

Cypermethrin, a commonly used domestic and agricultural pyrethroid pesticide, is widely considered detrimental to the environment and to many organisms because of its residual property and toxicity. Cellulophaga lytica DAU203, isolated from coastal sediment, was chosen because it degrade cypermethrin. Cellulophaga lytica DAU203 effectively degraded cypermethrin, as the utilized carbon source and substrate, in a mineral salt medium. Effective factors, such as carbon source, nitrogen source, initial pH, and temperature, for cypermethtin biological degradation by Cellulophaga lytica DAU203 were analyzed by one factor at a time method. Temperature ($22{\sim}42^{\circ}C$), initial pH (5~9), and yeast extract concentration (0.1~2.5%[w/v]) were selected as the three most important factors. There were optimized at $33.4^{\circ}C$, pH 7.7, and 2.4%(w/v) by response surface methodology, respectively. The Box- Behnken design consisting of 46 experimental runs with three replicates was used to optimize the independent variables which significantly influenced the cypermethrin biological degradation. This model for cypermethrin degradation by Cellulophaga lytica DAU203 is highly significant (p<0.05). Under the optimized condition, Cellulophaga lytica DAU203 degraded approximately 83.7 % of the cypermethrin within 5 days. These results suggest that Cellulophaga lytica DAU203 may be useful for the biological degradation of cypermethrin in cypermethrin-contaminated environments.

• Korean Journal of Microbiology
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• v.44 no.4
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• pp.311-316
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• 2008

In this study, biological PCE degradation by using a BTEX degrading bacterium, named BJ10, under aerobic conditions in the presence of toluene was examined. According to morphological, physiological characteristics, 16S rDNA sequencing and fatty acid analysis, BJ10 was classified as Pseudomonas putida. As a result of biological PCE degradation at low PCE concentrations (5 mg/L), PCE removal efficiency by P. putida BJ10 was 52.8% for 10 days, and PCE removal rate was 5.9 nmol/hr (toluene concentration 50 mg/L, initial cell density 1.0 g (wet weight)/L, temperature 30, pH 7 and DO $3.0{\sim}4.2\;mg/L$. At high PCE concentration (100 mg/L), PCE removal efficiency by P. putida BJ10 was 20.3% for 10 days, and PCE removal rate was 46.0 nmol/hr under the same conditions. The effects of various toluene concentration (5, 25, 50, 100, 200 mg/L) on PCE degradation were examined under the same incubation conditions. The highest PCE removal efficiency of PCE was 57.0% in the initial PCE concentration of 10 mg/L in the presence of 200 mg/L toluene for 10 days. Furthermore, the additional injection of 5.5 mg/L PCE (total 7.6 mg/L) made 63.0% degradation for 8 days in the presence of 50 mg/L toluene under the same conditions. Its removal rate was 13.5 nmol/hr, which was better than the initial removal rate (8.1 nmol/hr).

• Journal of Microbiology and Biotechnology
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• v.16 no.2
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• pp.232-239
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• 2006

The microbial activity and bacterial community structure of activated sludge reactors, which treated free cyanide (FC), zinc-complexed cyanide (ZC), or nickel-complexed cyanide (NC), were studied. The three reactors (designated as re-FC, re-ZC, and re-NC) were operated for 50 days with a stepwise decrease of hydraulic retention time. In the re-FC and re-ZC reactors, FC or ZC was almost completely removed, whereas approximately 80-87% of NC was removed in re-NC. This result might be attributed to the high toxicity of nickel released after degradation of NC. In the batch test, the sludges taken from re-FC and re-ZC completely degraded FC, ZC, and NC, whereas the sludge from re-NC degraded only NC. Although re-FC and re-ZC showed similar properties in regard to cyanide degradation, denaturing gradient gel electrophoresis (DGGE) analysis of the 16S rRNA gene of the bacterial communities in the three reactors showed that bacterial community was specifically acclimated to each reactor. We found several bacterial sequences in DGGE bands that showed high similarity to known cyanide-degrading bacteria such as Klebsiella spp., Acidovorax spp., and Achromobacter xylosoxidans. Flocforming microorganism might also be one of the major microorganisms, since many sequences related to Zoogloea, Microbacterium, and phylum TM7 were detected in all the reactors.