• Proceedings of the Earthquake Engineering Society of Korea Conference
• /
• 2001.09a
• /
• pp.44-51
• /
• 2001

We compare with earthquake parameters of KMA(Korea Meteorological Administration) and ISC(International Seismological Centre) to understand characteristics of earthquake using 30 earthquakes data acquired from 1978 to 1998 in Korea. We calculate difference of KMA between ISC epicentral distance and analyze for magnitude and year. Difference of epicentral distance decreases according to increase of magnitude and have no concern with year. That is the lowest in case of earthquake occurring in land of south Korea. We estimate relation formula for magnitude of KMA and ESC. The result can be expressed in KMA( $M_{L}$) and ISC( $m_{b}$ ) as $M_{L}$$^{KMA}$ = 0.70* $m_{b}$ $^{ISC}$+1.03 and in KMA( $M_{L}$) and ISC( $M_{L}$ as $M_{L}$$^{KMA}$=0.47* $M_{L}$$^{ISC}$+1.37X> ISC/+1.371.371.37

• Journal of Microbiology and Biotechnology
• /
• v.18 no.10
• /
• pp.1672-1677
• /
• 2008

IscR (iron-sulfur cluster regulator) has been reported to be a repressor of the iscRSUA operon, and in vitro transcription reactions have revealed that IscR has a repressive effect on the iscR promoter in the case of [$Fe_{2}S_{2}$] cluster loading. In the present study, the iscR gene from A. ferrooxidans ATCC 23270 was cloned and successfully expressed in Escherichia coli, and then purified by one-step affinity chromatography to homogeneity. The molecular mass of the IscR was 18 kDa by SDS-PAGE. The optical and EPR spectra results for the recombinant IscR confirmed that an iron-sulfur cluster was correctly inserted into the active site of the protein. However, no [$Fe_{2}S_{2}$] cluster was assembled in apoIscR with ferrous iron and sulfide in vitro. Therefore, the [$Fe_{2}S_{2}$] cluster assembly in IscR in vivo would appear to require scaffold proteins and follow the Isc "AUS" pathway.

• International Commerce and Information Review
• /
• v.12 no.3
• /
• pp.335-359
• /
• 2010

The purpose of this study is to interpret the articles revision of the 2009 ISC(Cargo) compared to the 1982. The result of this study is summarized as followings: 1) the 'clause' attached to article in 1982 ISC(Cargo) was deleted in the revision of 2009 ISC(Cargo). 2) 2009 ISC(Cargo) is characterized as the marine insurance firms' acceptance of new environment change, limitation in causation and subject-matter insured, expansion of insurance period, and limited revision. 3) The assured has a large range of choice in 2009 ISC(Cargo) even though both 1982 ISqCargo) and 2009 ISC(Cargo) would be existed further. 4) There are few studies which have a focus on the impact of the relationship between responsibility of the insurer and opportunity of the assured on rate of premium. In the future, the studies on clauses, relationship among clauses, relationship between clause and rate of premium are needed in the 2009 ICC(Air), 2009 IWC(Air Cargo), 2009 ISC(Air Cargo), 2009 IWC(sending by post) et al.

• Journal of the Korean Magnetic Resonance Society
• /
• v.28 no.1
• /
• pp.1-5
• /
• 2024

IscU, the iron-sulfur (Fe-S) cluster scaffold protein, is an essential protein for biogenesis of Fe-S clusters. Previous studies showed that IscU manifests a metamorphic structural feature; at least two structural states, namely the structured state (S-state) and the disordered state (D-state), interconverting in a physiological condition, was observed. Moreover, subsequent studies demonstrated that the metamorphic flexibility of IscU is important for its Fe-S cluster assembly activity as well as for an efficient interaction with various partner proteins. Although solution nuclear magnetic resonance (NMR) spectroscopy has been a useful tool to investigate this protein, the detailed molecular mechanism that sustains the structural heterogeneity of IscU is still unclear. To tackle this issue, we applied a high-pressure NMR (HP-NMR) technique to the IscU variant, IscU(I8K), which shows an increased population of the S-state. We found that the equilibrium between the S- and D-state was significantly perturbed by pressure application, and the specific regions of IscU exhibited more sensitivity to pressure than the other regions. Our results provide novel insights to appreciate the dynamic behaviors of IscU and the related versatile functionality.

• Journal of Microbiology and Biotechnology
• /
• v.32 no.9
• /
• pp.1110-1119
• /
• 2022

Fe-S clusters are versatile and essential cofactors that participate in multiple and fundamental biological processes. In Escherichia coli, the biogenesis of these cofactors requires either the housekeeping Isc pathway, or the stress-induced Suf pathway which plays a general role under conditions of oxidative stress or iron limitation. In the present work, the Fe-S cluster assembly Isc and Suf systems of acidophilic Bacteria and Archaea, which thrive in highly oxidative environments, were studied. This analysis revealed that acidophilic microorganisms have a complete set of genes encoding for a single system (either Suf or Isc). In acidophilic Proteobacteria and Nitrospirae, a complete set of isc genes (iscRSUAX-hscBA-fdx), but not genes coding for the Suf system, was detected. The activity of the Isc system was studied in Leptospirillum sp. CF-1 (Nitrospirae). RT-PCR experiments showed that eight candidate genes were co-transcribed and conform the isc operon in this strain. Additionally, RT-qPCR assays showed that the expression of the iscS gene was significantly up-regulated in cells exposed to oxidative stress imposed by 260 mM Fe₂(SO₄)₃ for 1 h or iron starvation for 3 h. The activity of cysteine desulfurase (IscS) in CF-1 cell extracts was also upregulated under such conditions. Thus, the Isc system from Leptospirillum sp. CF-1 seems to play an active role in stressful environments. These results contribute to a better understanding of the distribution and role of Fe-S cluster protein biogenesis systems in organisms that thrive in extreme environmental conditions.

• The Journal of Korean Society for Radiation Therapy
• /
• v.19 no.2
• /
• pp.131-141
• /
• 2007

Purpose: Try to compare dose distribution and lung dose of radiation treatment plan of the breast cancer that used Irregular Surface Compensator (ISC) and treatment plan that used a wedge filter. Materials and Methods: Established a treatment plan to be distributed over 95% of prescription dose (5,040 cGy) of the two tangent-half fields that used a wedge filter and ISC at a breast organization as made to breast cancer patient having an irregular surfaces after surgery. Compared high dose area and DVH, and verified a treatment plan as used film with rectangular phantom. Results: Maximum dose point in breast tissue appeared to 107.5% in case of tangent-half fields Tx plan that used a wedge filter, and lung volumes exposed above 20 Gy by 7.63%. In case of ISC, maximum dose point in breast tissue appeared to 106.4%, and lung volumes exposed above 20 Gy by 6.5%. The film measurement results that used phantom, 105$\sim$110% high dose region was distributed to the upper part and both edges of phantom. However in case of ISC, appeared by 100$\sim$105% dose conformity distribution. Conclusion: In general, the Irregular Surface Compensator (ISC) can improve the dose conformity of breast tissues, as well as reduced hot spots in the lung and in the breast. Such an advantage by using ISC technique is more beneficial for patients who have more irregular surfaces after surgery.

• Journal of Microbiology and Biotechnology
• /
• v.19 no.12
• /
• pp.1520-1526
• /
• 2009

We have identified the iscR (PA3815) gene encoding an iron-sulfur cluster assembly regulator homolog as one of the genes required for peroxide resistance in Pseudomonas aeruginosa PA14. Here, we present the phenotypic characterization of an iscR deletion mutant in terms of KatA expression, stress responses, and virulence. The iscR null mutant exhibited reduced KatA activity at the posttranslational level, hypersensitivity to hydrogen peroxide, and virulence-attenuation in Drosophila melanogaster and mouse peritonitis models. These phenotypes were fully restored by multicopy-based expression of katA. These results suggest that the requirement of IscR in P. aeruginosa is related to the proper activity of KatA, which is crucial for peroxide resistance and full virulence of this bacterium.

• Journal of the Korean Magnetic Resonance Society
• /
• v.24 no.3
• /
• pp.86-90
• /
• 2020

Iron-sulfur (Fe-S) clusters are one of the most ancient yet essential cofactors mediating various essential biological processes. In prokaryotes, Fe-S clusters are generated via several distinctive biogenesis mechanisms, among which the ISC (Iron-Sulfur Cluster) mechanism plays a house-keeping role to satisfy cellular needs for Fe-S clusters. The Escherichia coli ISC mechanism is maintained by several essential protein factors, whose structural characterization has been of great interest to reveal mechanistic details of the Fe-S cluster biogenesis mechanisms. In particular, nuclear magnetic resonance (NMR) spectroscopic approaches have contributed much to elucidate dynamic features not only in the structural states of the protein components but also in the interaction between them. The present minireview discusses recent advances in elucidating structural features of IscU, the key player in the E. coli ISC mechanism. IscU accommodates exceptional structural flexibility for its versatile activities, for which NMR spectroscopy was particularly successful. We expect that understanding to the structural diversity of IscU provides critical insight to appreciate functional versatility of the Fe-S cluster biogenesis mechanism.

• Journal of Microbiology and Biotechnology
• /
• v.18 no.6
• /
• pp.1070-1075
• /
• 2008

IscA was proposed to be involved in the iron-sulfur cluster assembly encoded by the iscSUA operon, but the role of IscA in the iron-sulfur cluster assembly still remains controversial. In our previous study, the IscA from A. ferrooxidans was successfully expressed in Escherichia coli, and purified to be a [$Fe_4S_4$] -cluster-containing protein. Cys35, Cys99, and Cys101 were important residues in ligating with the [$Fe_4S_4$] cluster. In this study, Asp97 was found to be another ligand for the iron-sulfur cluster binding according to site-directed mutagenesis results. Molecular modeling for the IscA also showed that Asp97 was a strong ligand with the [$Fe_4S_4$] cluster, which was in good agreement with the experimental results. Thus, the [$Fe_4S_4$] cluster in IscA from A. ferrooxidans was ligated by three cysteine residues and one aspartic acid.

• Archives of Pharmacal Research
• /
• v.20 no.6
• /
• pp.550-554
• /
• 1997

Chlorambucil is known to alkylate primarily N7 of guanine and N3 of adenine to induce DNA monofunctional adducts and interstrand cross-links (ISC). We have investigated the sequence specificity for DNA ISC induced by chlorambucil using duplex oligomers containing a defined cross-linkable sequences $ 5^{I}-A*TT, 5^{I}-G*TTor5^{I}-G*CC$ under bar which asterisk indicates the potential cross-linking site and underlined base indicates the potential cross-linking site on the opposite strand. An analysis of 20% denaturing polyacrylamide gel electrophoresis showed that chlorambucil was albe to induce DNA ISC in the duplex oligomers containing a sequence $5^I-GCC$. The formation of DNA ISC was not observed in the duplex oligomers containing sequences $5^I-ATT$. or $5^I-GTT$. These results indicate that chlorambucil induces guanine-guanine DNA ISC but not guanine-adenine or adenine-adenine DNA ISC. In addition, we have tested the ability of chlorambucil to induce DNA ISC within $5^I-GNNC$ or $5^I-GNNC$sequences using duplex oligomers containing the sequence$5^I-G^4G^3G^2^C$. The result of DNA strand cleavage assay showed that DNA ISC was formed at the $5^I-GGC$ sequence (an 1,3 cross-link, $G^1-G^3$) but not at $5^I-GGGC$ (an 1,4 cross-link, $G^1-G^4$) or $5^I-GC$ sequence (an 1,2 cross-link, $G^1-G^2$).