• Journal of Microbiology and Biotechnology
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• v.31 no.7
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• pp.912-920
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• 2021

SOS response is a conserved response to DNA damage in prokaryotes and is negatively regulated by LexA protein, which recognizes specifically an "SOS-box" motif present in the promoter region of SOS genes. Myxococcus xanthus DK1622 possesses a lexA gene, and while the deletion of lexA had no significant effect on either bacterial morphology, UV-C resistance, or sporulation, it did delay growth. UV-C radiation resulted in 651 upregulated genes in M. xanthus, including the typical SOS genes lexA, recA, uvrA, recN and so on, mostly enriched in the pathways of DNA replication and repair, secondary metabolism, and signal transduction. The UV-irradiated lexA mutant also showed the induced expression of SOS genes and these SOS genes enriched into a similar pathway profile to that of wild-type strain. Without irradiation treatment, the absence of LexA enhanced the expression of 122 genes that were not enriched in any pathway. Further analysis of the promoter sequence revealed that in the 122 genes, only the promoters of recA2, lexA and an operon composed of three genes (pafB, pafC and cyaA) had SOS box sequence to which the LexA protein is bound directly. These results update our current understanding of SOS response in M. xanthus and show that UV induces more genes involved in secondary metabolism and signal transduction in addition to DNA replication and repair; and while the canonical LexA-dependent regulation on SOS response has shrunk, only 5 SOS genes are directly repressed by LexA.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.8
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• pp.3516-3541
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• 2018

Task scheduling is one of the most challenging aspects of cloud computing nowadays, and it plays an important role in improving overall performance in, and services from, the cloud, such as response time, cost, makespan, and throughput. A recent cloud task-scheduling algorithm based on the symbiotic organisms search (SOS) algorithm not only has fewer specific parameters, but also incurs time complexity. SOS is a newly developed metaheuristic optimization technique for solving numerical optimization problems. In this paper, the basic SOS algorithm is reduced, and chaotic local search (CLS) is integrated into the reduced SOS to improve the convergence rate. Simulated annealing (SA) is also added to help the SOS algorithm avoid being trapped in a local minimum. The performance of the proposed SA-CLS-SOS algorithm is evaluated by extensive simulation using the Matlab framework, and is compared with SOS, SA-SOS, and CLS-SOS algorithms. Simulation results show that the improved hybrid SOS performs better than SOS, SA-SOS, and CLS-SOS in terms of convergence speed and makespan.

• Journal of Radiation Industry
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• v.7 no.2_3
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• pp.109-113
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• 2013

In a previous study, a relatively high dose of gamma radiation (1 kGy) did not fully induce typical SOS genes such as sulA, recA, recN, and din in Salmonella Typhimurium (S. Typhimurium) (Lim et al. 2008, Gene expression profiles following high-dose exposure to gamma radiation in Salmonella enterica serovar Typhimuium. J. Radiat. Ind. 3:111-119). In this study, we examined changes in the transcriptional repertoire of S. Typhimurium after a dose of 10 Gy using DNA microarrays. It was found that more than half (~65%) of the 26 up-regulated genes belong to the SOS regulon: ten genes are typical SOS genes, and seven genes are Salmonella prophage genes, which are known to be activated by LexA cleavage. Among 29 down-regulated genes, the function of five genes with the most decreased expression is associated with carbohydrate transport and energy production. This suggests that upon exposure to gamma radiation cells may cease growing by reducing the metabolic activity, and repair DNA damage using a DNA repair system such as the SOS response system. The difference in expression of the SOS genes between a high (1 kGy) and low (10 Gy) dose of radiation shows the possibility that cells may opt for one of multiple regulatory circuits in response to the specific gamma radiation dose.

• Korean Journal of Food Science and Technology
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• v.30 no.6
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• pp.1464-1469
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• 1998

SOS Chromotest and Ames test were carried out to evaluate the mutagenicity of three chloropropanols. In the SOS Chromotest, 3-monochloro-l,2-propanediol (3-MCPD) and 2,3-dichloro-1-propanol (2,3-DCP) except for 1,3-dichloro-2-propanol (1,3-DCP) induced SOS response in Escherichia coli PQ37 with dose-response relationship and 2,3-DCP was far more genotoxic than 3-MCPD. The genotoxic activities of both compounds, however, were very lower in E. coli PQ35 (PQ37 $uvrA^+)$ as compared to them in E. coli PQ37, whereas much higher in E. coli PQ243 (PQ37 tagA alkA). These results indicate that there are at least two types of DNA lesions caused by these compounds; one is a excision-repairable and the other is 3-methyladenine or any similar lesion which is excision-unrepairable and can induce adaptive response. In Salmonella typhimurium TA100, all the compounds showed strong mutagenicities, establishing the following genotoxic order: 2,3-DCP>3-MCPD>1,3-DCP. But the mutagenic activities were very low in S. typhimurium TA98 and TA97a. These results suggest that the mutation by chloropropanols can be induced by the DNA lesions causing base-pair substitutions. From the result that the mutagenicities of 3-MCPD and 2,3-DCP in S. typhimurium TA1535 were very low as compared to those in S. typhimurium TA100, it was appeared that the mutations by both compounds necessitate error-prone SOS repair.

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2004.05a
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• pp.84-84
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• 2004

• Proceedings of the Korean Society of Applied Pharmacology
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• 1993.04a
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• pp.174-174
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• 1993

목적: Cinnamic acid의 유도체들중에서 항돌연변이 효과가 보고된 바 있어, 본 연구에서는 E. coil PQ37균주를 사용한 SOS chromotest를 이용하여 약 170개 cinnamic acid의 유도체들의 항돌연변이 효과를 확인하고자 하였고, 1차로 확인된 수종의 유도체들에 대한 결과를 보고하고자 한다. 방법: SOS chromotest는 sul A:: lacz fusion strain 인 E. coli PQ37 에서의 chemical로 인한 DNA damage에 대한 SOS response를 $\beta$-galactosidase enzyme activity level로서 측정하는 실험이며, m-RNA 또는 protein synthesis에 대한 test chemicals의 cytotoxic저해효과를 알아보기 위하여 alkaline phosphatase를 병행측정하여 보완하였다. 결과 및 고찰: (－)S－9 경우는 4-nitroquinoline 1-oxide(4-NQO)를 유도물질로 하였으며 대략 Induction factor가 9.7 정도였고, (＋)S－9의 경우는 aflatoxinB$_1$을 유도물질로 하였고 이때의 Induction factor는 13.8 정도였다. 이결과 1차로 test된 cinnamic acid유도체 6개중에서 RK001, RK002, RK003, RK004, RK005는 거의 항돌연변이 효과를 나타내지 않았으나, RK006은 항돌연변이 효과를 보여주어 이들의 Structure-Activity Relationship (SAR) 및 Dose-response와 RK006의 항돌연변이 효과의 mechanism에 관해 M13 mp2 viral DNA의 유전자 염기서열을 이용하여 항돌연변이 기전연구를 수행중이다.

• Clinical and Experimental Pediatrics
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• v.62 no.7
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• pp.274-280
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• 2019

Purpose: To analyze the growth response to growth hormone (GH) therapy in prepubertal patients with Noonan syndrome (NS) harboring different genetic mutations. Methods: Twenty-three patients with prepubertal NS treated at Pusan National University Children's Hospital between March 2009 and July 2017 were enrolled. According to the disease-causing genes identified, the patients with NS were divided into 4 groups. Three groups were positive for mutations of the PTPN11, RAF1, and SOS1 genes. The five genes undetected (FGU) group was negative for PTPN11, RAF1, SOS1, KRAS, and BRAF gene mutations. The influence of genotype was retrospectively analyzed by comparing the growth parameters after GH therapy. Results: The mean chronological age at the start of GH treatment was $5.85{\pm}2.67years$. At the beginning of the GH treatment, the height standard deviation score (SDS), growth velocity (GV), and lower levels of insulin-like growth factor-1 (IGF)-1 levels were not statistically different among the groups. All the 23 NS patients had significantly increased height SDS and serum IGF-1 level during the 3 years of treatment. GV was highest during the first year of treatment. During the 3 years of GH therapy, the PTPN11, RAF1, and SOS1 groups showed less improvement in height SDS, IGF-1 SDS, and GV, and less increase in bone age-to-chronological age ratio than the FGU group. Conclusion: The 3-year GH therapy in the 23 prepubertal patients with NS was effective in improving height SDS, GV, and serum IGF-1 levels. The FGU group showed a better response to recombinant human GH therapy than the PTPN11, RAF1, and SOS1 groups.

• Journal of Korean Academy of Nursing
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• v.23 no.2
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• pp.299-315
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• 1993

Koreans are one of the fastest growing immigrant groups in America. Stress responses and stressors among this large cultural minority has been rarely been studied by nursing researchers. Adjusting to life in foreign country produces a great deal of stress. Differences in culture, language, expectations and social behavior can lead to misunderstandings between health care providers and clients. These misunderstandings are not well accounted for in health assessment. This study investigated the relationship between life events or / and daily activities as a stressor and the symptoms of stress among a sample of Korean immigrants in America. The symptoms of stress scale (SOS) was used to identify stress responses and open-ended questions were used to identify life events and daily activities considered by the respondents to be stressful. A simple random sample of 283 subjects was selected from the Directory of the Korean Society of Chicago, New York, Los Angeles, Philadelphia and Seattle. Demographically, the subjects ranged in age from 20 to 69 years, and the percentage of women and men was approximately 50% each. Almost ninety percent of the subjects were highly educated, 17% owners of business, 19% white collar professionals, 14% employed in sales or as skilled /unskilled labor, 27% as housewives and students and 3％ had no occupation. The total group SOS mean was 0.8042 ; the SOS men for man was 0.7371, and for women was 0.8713. The stress response of this subject group was high, -the stress response of women higher than that for men. In an earlier study(June, 1992) with another sample, the total mean SOS score was similar to this one. The main stressful life events or / and daily activities were, in order, economic problems (N=97), interpersonal problems (N=68), children care problems (N=258), health problems (N=49), communication problems (N=42), family problems (N=38), worry about future career (N=36), and religious problems (N=25). There was a significant difference in the SOS means between the group that expressed life events or / and daily activities to be stressful and the group that did not. Interpersonal relationships and economic and family problems were stressors for those who complained about peripheral manifestations. cardiopulmonary symptoms, central-neurological symptoms, gastrointestinal symptoms, muscle ten-sion, habitual patterns, depression, anxiety, emotional irritability and cognitive disorganization. In summary, interpersonal relationships and economic and family problems influenced stress response manifestations. Income, the number of people in the family, the year of immigration. the level of education, and marital status were related to physiological and psychosocial stress responses.

• Journal of Microbiology and Biotechnology
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• v.24 no.9
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• pp.1232-1237
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• 2014

Lycopene, which is a well-known red carotenoid pigment, has been drawing scientific interest because of its potential biological functions. The current study reports that lycopene acts as a bactericidal agent by inducing reactive oxygen species (ROS)-mediated DNA damage in Escherichia coli. Lycopene treatment elevated the level of ROS-in particular, hydroxyl radicals ($^*OH$)-which can damage DNA in E. coli. Lycopene-induced DNA damage in bacteria was confirmed and we also observed cell filamentation caused by cell division arrest, an indirect marker of the DNA damage repair system, in lycopene-treated E. coli. Increased RecA expression was observed, indicating activation of the DNA repair system (SOS response). To summarize, lycopene exerts its antibacterial effects by inducing $^*OH$-mediated DNA damage that cannot be ameliorated by the SOS response. Lycopene may be a clinically useful adjuvant for current antimicrobial therapies.

• Journal of Microbiology and Biotechnology
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• v.23 no.9
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• pp.1293-1303
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• 2013

Antibiotic resistance of soilborne Acinetobacter species has been poorly explored. In this study, norfloxacin resistance of a soil bacterium, Acinetobacter oleivorans DR1, was investigated. The frequencies of mutant appearance of all tested non-pathogenic Acinetobacter strains were lower than those of pathogenic strains under minimum inhibitory concentration (MIC). When the quinolone-resistance-determining region of the gyrA gene was examined, only one mutant (His78Asn) out of 10 resistant variants had a mutation. Whole transcriptome analysis using a RNA-Seq demonstrated that genes involved in SOS response and DNA repair were significantly up-regulated by norfloxacin. Determining the MICs of survival cells after norfloxacin treatment confirmed some of those cells were indeed persister cells. Ten colonies, randomly selected from among those that survived in the presence of norfloxacin, did not exhibit increased MIC. Thus, both the low mutation frequency of the target gene and SOS response under norfloxacin suggested that persister formation might contribute to the resistance of DR1 against norfloxacin. The persister frequency increased without a change in MIC when stationary phase cells, low growth rates conditions, and growth-deficient dnaJ mutant were used. Taken together, our comprehensive approach, which included mutational analysis of the target gene, persister formation assays, and RNA sequencing, indicated that DR1 survival when exposed to norfloxacin is related not only to target gene mutation but also to persister formation, possibly through up-regulation of the SOS response and DNA repair genes.