• 식물병연구
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• 제22권4호
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• pp.276-283
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• 2016

2013년부터 2016년까지 P. syringae pv. actinidiae에 의한 궤양병에 감염된 것으로 확인된 과수원수는 202개였는데, Psa2가 73개 과수원에서 검출되었고 Psa3는 129개 과수원에서 검출되었다. 2015년에 비해 2016년 Psa2에 감염된 과수원은 거의 증가하지 않았지만 Psa3에 감염된 과수원은 두 배 가량 증가했다. 우리나라에서 재배하고 있는 키위 품종들 중에서 일부 토종다래를 제외한 모든 키위 품종들에서 Psa3가 검출되어 아직까지 Psa3에 저항성인 품종은 없다는 것이 확인되었다. 조사된 품종들 중에서 골드키위 품종인 Hort16A와 제시골드와 레드키위 품종인 홍양이 Psa3에 가장 감수성이었다. 경남지역에서 역학조사와 RAPD 분석 결과 2014년 홍양 과수원에서 최초 Psa3에 의한 궤양병은 중국에서 수입한 Psa3에 오염된 꽃가루에 의해 발생했고, 2016년 경남 사천과 고성 지역의 과수원들에서 궤양병의 대발생은 홍양 과수원으로부터 근처 제시골드와 헤이워드 과수원으로 2차감염에 의한 Psa3의 급속한 확산 때문으로 추정된다.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2004년도 추계학술발표회 발표논문집
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• pp.505-506
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• 2004

• Journal of Microbiology and Biotechnology
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• 제17권5호
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• pp.840-846
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• 2007

Human prostate-specific antigen(PSA), a 33 kDa serine protease with comprehensive homology to glandular kallikrein, is secreted from prostatic tissue into the seminal fluid and enters into the circulation. The level of PSA increases in the serum of patients with prostatic cancer and hence is widely employed as a marker of the disease status. In particular, an enzymatically active PSA that is a form cleaved at the N-terminal seven-amino-acids prosequence, APLILSR, of proPSA may play an important roll in the progression of prostate cancer. Thus, the presence of the active form would selectively discriminate the cancer from benign prostatic hyperplasia. In this study, we developed a convenient purification method for the acquisition of active PSA and proPSA. Recombinant proPSA and active PSA were expressed directly in Escherichia coli, easily and efficiently isolated from inclusion bodies, refolded, and purified. Moreover, the enzymatic activity of the recombinant active PSA was confirmed as serine protease using chromogenic chymotrypsin substrate. This purified active PSA could be further applied to scrutinize the biological or conformational characteristics of the protein and to develop specific diagnostic and/or therapeutic agents against prostate cancer.

• 한국안전학회지
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• 제34권5호
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• pp.159-166
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• 2019

The seismic PSA is to probabilistically estimate the potential damage that a large earthquake will cause to a nuclear power plant. It integrates the probabilistic seismic hazard analysis, seismic fragility analysis, and system analysis and is utilized to identify seismic vulnerability and improve seismic capacity of nuclear power plants. Recently, the seismic risk of domestic multi-unit nuclear power plant sites has been evaluated after the Great East Japan Earthquake and Gyeongju Earthquake in Korea. However, while the currently available methods for system analysis can derive basic required results of seismic PSA, they do not provide the detailed results required for the efficient improvement of seismic capacity. Therefore, for in-depth seismic risk evaluation, improved system analysis method for seismic PSA has become necessary. This study develops a system analysis method that is not only suitable for multi-unit seismic PSA but also provides risk information for the seismic capacity improvements. It will also contribute to the enhancement of the safety of nuclear power plants by identifying the seismic vulnerability using the detailed results of seismic PSA. In addition, this system analysis method can be applied to other external event PSAs, such as fire PSA and tsunami PSA, which require similar analysis.

• 한국안전학회지
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• 제31권5호
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• pp.187-194
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• 2016

A single fire event within a fire area can cause multiple initiating events considered in internal events probabilistic safety assessment (PSA). For an example, a fire event in turbine building fire area can cause a loss of the main feed-water and loss of off-site power initiating events. This fire initiating event could result in special plant responses beyond the scope of the internal events PSA model. One approach to address a fire initiating event is to develop a specific fire event tree. However, the development of a specific fire event tree is difficult since the number of fire event trees may be several hundreds or more. Thus, internal fire events PSA model has been generally constructed by modifications of the pre-developed internal events PSA model. New accident sequence logics not covered in the internal events PSA model are separately developed to incorporate them into the fire PSA model. Recently, many fire PSA models have fire induced initiating event fault trees not shown in an internal event PSA model. Up to now, there has been no analytical comparative study on the constructions of fire events PSA model using internal events PSA model with and without fault trees of initiating events. In this study, the changing process of internal events PSA model to fire events PSA model is analytically presented and discussed.

• Natural Product Sciences
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• 제10권6호
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• pp.277-283
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• 2004

Psammaplin A (PSA), a naturally occurring biophenolic compound has been demonstrated to deliver significant cytotoxicity to many cancer cell lines. In this article, we investigated the effect of PSA on cell cycle progression of lung cancer cells (A549). It was found that PSA could slightly perturb the cell cycle progression of A549 cells and lead to the cell cycle arrest at G2/M phase, indicating PSA might disturb the mitosis process of A549 cells. In addition, inspired by the two phenolic groups in the structure of PSA, the antioxidant activity of it has been evaluated. Although PSA was weak in scavenging the stable free radical 1,1-diphenyl-2-picrylhyrazyl (DPPH), it showed stronger ABTS radical scavenging activity than ascorbic acid in TEAC assay. Furthermore, it was found that PSA could effectively prevent DNA strand scission induced by oxidative stress. These results suggest that PSA have both cell cycle regulation and antioxidant activities. Herein, we suggest that PSA would be a very interesting and promising candidate to be developed as a multi-function drug.

• Asian Pacific Journal of Cancer Prevention
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• 제16권16호
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• pp.7085-7088
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• 2015

Background: The high incidence of prostate cancer as the most common malignancy in males in many countries raises the question of developing reliable detection tests. The prostate specific antigen (PSA) test is the most widely used for screening for prostate cancer; however, its low specificity elevates the number of unnecessarily biopsies. Serum human kallikrein-2 (hK2) is considered as a promising marker, and especially its ratio to fPSA, for predicting the presence of malignancy to select the best choice referring to biopsy or surveillance. In this study, we investigated the role of hK2 and its combinations with other markers to discriminate prostate cancer from benign diseases in Syrian patients. Materials and Methods: In this prospective oriented cross-sectional cohort study, serum samples were collected from patients referred to many Hospitals in Damascus, Syria, between May 2011 and March 2012, and diagnosed with biopsy proven benign prostate hyperplasia (BPH) or prostate cancer (PCa). Serum was analyzed for hK2, PSA and fPSA, and the ratios of fPSA/PSA and hK2/fPSA were calculated. Results: We found that mean hK2/fPSA ratios were significantly higher (P=0.01) in prostate cancer patients than in the BPH or control groups. Also the ratio hk2/fPSA gave the largest area under the curve (AUC:0.96) which was significantly larger than for fPSA/PSA (AUC:0.41) indicative of higher specificity. Conclusions: Our results demonstrate that the ratio of hK2/fPSA might be superior to the use of fPSA/PSA alone. The hK2 could be shown to enhance the early detection of prostate cancer; especially the ratio hK2/fPSA improves specificity and hence may reduce the number of negative biopsies.

• The Plant Pathology Journal
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• 제32권6호
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• pp.545-551
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• 2016

A bacterial pathogen, Pseudomonas syringae pv. actinidiae (Psa), is a causal agent of kiwifruit bacterial canker worldwide. Psa biovar 3 (Psa3) was first detected in 2011 at an orchard in Dodeok-myeon, Goheung-gun, Jeonnam Province in Korea. In this study, we present the results of an epidemiological study regarding Psa3 occurrence on kiwifruit orchards in Korea for the period of 2013 to 2015. Since the first detection of Psa3 in 2011, there was no further case reported by 2013. However, Psa3 was rapidly spreading to 33 orchards in 2014; except for three orchards in Sacheon-si, Gyeongnam Province, most cases were reported in Jeju Island. Entering 2015, bacterial canker by Psa3 became a pandemic in Korea, spreading to 72 orchards in Jeju Island, Jeonnam, and Gyeongnam Provinces. Our epidemiological study indicated that the first Psa3 incidence in 2011 might result from an introduction of Psa3 through imported seedlings from China in 2006. Apart from this, it was estimated that most Psa3 outbreaks from 2014 to 2015 were caused by pollens imported from New Zealand and China for artificial pollination. Most kiwifruit cultivars growing in Korea were infected with Psa3; yellow-fleshed cultivars (Yellow-king, Hort16A, Enza-gold, Zecy-gold, and Haegeum), red-fleshed cultivars (Hongyang and Enza-Red), green-fleshed cultivars (Hayward and Daeheung), and even a kiwiberry (Skinny-green). However, susceptibility to canker differed among cultivars; yellow- and red-fleshed cultivars showed much more severe symptoms compared to the green-fleshed cultivars of kiwifruit and a kiwiberry.

• 생명과학회지
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• 제20권7호
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• pp.991-998
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• 2010

저산소상태(hypoxia)는 세포유형 및 성장조건에 따라 apoptosis를 유발하거나 또는 apoptosis의 진행을 억제한다. 저산소상태 유발물질인 cobalt chloride ($CoCl_2$) 역시 여러 세포 유형에서 apoptosis를 유발한다고 알려져 있으나 그 기작은 불명확하다. 본 연구에서는 PC-3 세포에서 $CoCl_2$에 의해 down-regulation되는 puromycin-sensitive aminopeptidase (PSA)의 세포 내 기능을 조사하였다. 본 연구 결과, PC-3 세포에 puromycin을 처리한 결과 전체 세포 집단의 약 42%에서 apoptosis가 유도되었다. PSA가 apoptosis에 관여하는지를 확인하고자 PSA siRNA로 내재성 PSA의 발현을 억제시킨 다음 apoptosis 연관 특성을 조사한 결과 PSA의 발현 억제에 의해 효과적으로 apoptosis가 유도되었다. 이러한 결과는 PC-3 세포에서 PSA가 세포생존에 중요한 역할을 할 것임을 보여주는 것이라 사료된다.

• Journal of Photoscience
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• 제3권1호
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• pp.23-28
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• 1996

To investigate the structure and function of photosystem I, cartridge mutagenesis technique was used to inactivate the psaB gene of photosystem I. From the screen, many strains which have potential defects in photosystem I were generated. Biochemical analysis revealed that B2, one of the mutant, had a reduced amount of chlorophyll. Electron transfer activitx from photosystem II to photosystem I as oxygen uptake was the rate of 64 % of wild type. Also B2 showed a decreased photosystem I activity when measured by 77 K fluorescence emission spectrum. Particularly, immunodetection analysis showed that the B2 had reduced amount of PsaA/PsaB, but a normal range of PsaC and PsaD. Here we present a photoheterotrophic mutant for psaB gene as a unique model strain for future study of structural/functional relationship and biogenesis of photosystem I.