• Journal of Life Science
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• v.19 no.1
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• pp.129-137
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• 2009

Calcium ($Ca^{2+}$) plays pivotal roles as an intracellular second messenger in response to a variety of stimuli, including light, abiotic. and biotic stresses and hormones. $Ca^{2+}$ sensor is $Ca^{2+}$-binding protein known to function in transducing signals by activating specific targets and pathways. Among $Ca^{2+}$-binding proteins, calmodulin (CaM) has been well reported to regulate the activity of down-stream target proteins in plants and animals. Especially plants possess multiple CaM genes and many CaM target proteins, including unique protein kinases and transcription factors. Thus, plants are possible to perceive different signals from their surroundings and adapt to the changing environment. However, the function of most of CaM or CaM-related proteins have been remained uncharacterized and unknown. Hence, a better understanding of the function of these proteins will help in deciphering their roles in plant growth, development and response to environmental stimuli. This review focuses on $Ca^{2+}$-CaM messenger system, CaM-associated proteins and their role in responses to external stimuli of both abiotic and biotic stresses in plants.

• Journal of Life Science
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• v.21 no.3
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• pp.444-450
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• 2011

Perchlorate ($ClO_4^-$) is a contaminant found in surface water and soil/ground water. Autotrophic perchlorate-reducing bacteria (PRB) use hydrogen gas ($H_2$) as an electron donor to remove perchlorate. Since iron corrosion can produce $H_2$, feasibility of autotrophic perchlorate-removal using zero-valent iron (ZVI) was examined in this study using activated sludge that is easily available from a wastewater treatment plant. Batch test showed that activated sludge microorganisms could successfully degrade perchlorate in the presence of ZVI. The perchlorate biodegradation was confirmed by molar yield of $Cl^-$ as perchlorate was degraded. Scanning electron microscope revealed that rod-shaped microorganisms on the surface of iron particles used for the autotrophic perchlorate-removal, suggesting that iron particles could serve as supporting media for the formation of biofilm as well. DGGE analyses revealed that microbial profile of the inoculum (activated sludge) was different from that of biofilm sample obtained from the ZVI-added enrichment culture used for $ClO_4^-$-degradation. A major band of the biofilm sample was most closely related to the class Clostridia.

• Journal of Life Science
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• v.25 no.2
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• pp.136-150
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• 2015

Pseudomonas syringae pathovar tabaci is a plant pathogenic bacterium that causes wildfire disease in tobacco plants. In P. syringae pv. tabaci, PsyI, a LuxI-type protein, acts as an AHL synthase, while primary and secondary sequence analysis of PsyR has revealed that it is a homolog of the LuxR-type transcriptional regulator that responds to AHL molecules. In this study, using phenotypic and genetic analyses in P. syringae pv. tabaci, we show the effect of PsyR protein as a quorum-sensing (QS) transcriptional regulator. Regulatory effects of PsyR on swarming motility and production of siderophores, tabtoxin, and N-acyl homoserine lactones were examined via phenotypic assays, and confirmed by quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR). Further qRT-PCR showed that PsyR regulates expression of these virulence genes in response to environmental signals. However, an upstream region of the gene was not bound with purified MBP-PsyR protein; rather, PsyR was only able to shift the upstream region of psyI. These results suggested that PsyR may be indirectly controlled via intermediate-regulatory systems and that auto-regulation by PsyR does not occur.

• Journal of Life Science
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• v.23 no.3
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• pp.462-469
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• 2013

Withaferin A is a steroidal lactone purified from the Indian medicinal plant Withania somnifera. It exhibits a wide variety of activities, including anti-tumor, anti-inflammation, and immunomodulation properties. In this review, we focused on the anti-cancer effects of withaferin A. Withaferin A inhibits cell proliferation, metastasis, invasion, and angiogenesis in cancer cells. Furthermore, it sensitized irradiation, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-, and doxorubicin-mediated apoptosis. The results showed that multiple mechanisms were involved in withaferin A-mediated anti-cancer effects. First, withaferin A increased intracellular reactive oxygen species (ROS) production and induced ER stress- and mitochondria-mediated apoptosis. Second, withaferin A inhibited the signaling pathways (Jak/STAT, Akt, Notch, and c-Met), which are important in cell survival, proliferation, and metastasis. Third, it induced apoptosis and inhibited cancer cell migration through the up-regulation of prostate apoptosis protein-4 (Par-4). Finally, withaferin A up-regulated pro-apoptotic protein expression levels through the inhibition of proteasome activity. Our findings suggested that withaferin A is a potential, potent therapeutic agent.

• Journal of Life Science
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• v.28 no.10
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• pp.1132-1139
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• 2018

The stability of diverse cellular proteins in eukaryotes is regulated via ubiquitination. Moreover, E3 ligase plays a crucial role in determining substrate specificity and transfers ubiquitins into the substrates during the ubiquitination process. As a type of multi-subunit E3 ligase, cullin4 (CUL4)-based E3 ligase (CRL4) complex is involved in a variety of cellular processes, such as hormonal and stress responses in plants. In spite of several reports on the versatile roles of CRL4 in various signalings in Arabidopsis, CRL4's function in rice has been poorly known. To learn about CRL4-mediated cellular processes in rice in more detail, OsCUL4 that exhibits the highest homology with Arabidopsis CUL4 was isolated, and its expression patterns in various tissues and in response to plant hormones and abiotic stresses were monitored. Exogenous application of ABA or cytokinin increased the transcript levels of the OsCUL4 gene. Moreover, OsCUL4 was significantly upregulated in response to drought and salt stresses. These findings imply that OsCUL4 may be functionally related to ABA- and/or cytokinin-mediated cellular responses. OsCUL4 directly interacted with OsDDB1, an adaptor protein of CRL4, indicating that OsCUL4 can act as a scaffold protein of CRL4. An expression study on the OsCUL4 gene from this report could be used as a starting point to elucidate cellular responses in which a CRL4-mediated ubiquitination process is involved in rice.

• Korean journal of applied entomology
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• v.55 no.4
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• pp.459-464
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• 2016

An outbreak of the migratory locust, Locusta migratoria, in the environment-friendly reclaimed plantations of forage crops in Sanyimyeon, Haenam-gun, Jellanam-do, Korea in August 2014 caused severe damages to various crops. Owing to its first occurrence in the Korean history, the causes underlying the outbreak and phase-transition of the migratory locust were not known. It is critical to establish the genetic relationship of the migratory locust in Sanyimyeon, Haenam-gun with the other previously reported strains in the world in order to understand the mechanisms responsible for its outbreak. The gene sequences of the 16S ribosomal RNA (rRNA) and displacement-loop (D-loop) of the mitochondria of various regional species of the migratory locust were used to perform the phylogenetic analysis. Our results suggested that the migratory locusts in Sanyimyeon, Haenam-gun are closely related with the Eurasian strains of the northern lineage. In future, these two mitochondrial genes can be used for elucidating the genetic population structures in migratory locusts in various regions. In addition, the sequence information of these genes can be used to enhance our understanding of the genetic basis of the outbreak of migratory locusts.

• Korean journal of applied entomology
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• v.56 no.4
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• pp.371-376
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• 2017

In a nationwide survey of the occurrence and density of the migratory locust (Locusta migratoria), high density was continuously observed in the reclaimed areas of Mangun-myeon in Muan-gun, Jeollanam-do, and Sanye-myeon in Haenam-gun, Jeollanam-do, Korea. We have analyzed the nucleotide sequences of NADH dehydrogenase subunit (NAD) 2, NAD4, and NAD5 genes in order to determine the origins of the migratory locusts at two sites. According to the analysis, the migratory locusts in Haenam-gun were closely related with those in Liaoning Province and Heilongjiang Province in the northeast China. In contrast, the migratory locusts in Muan-gun were most similar to those in Japan. Because Korean migratory locusts were not included in the previous global study on the evolution and migration of migratory locusts, we did not know the origin of Korean migratory locusts, earlier. Phylogenetic analyses this study suggested that the migratory locusts from the northeast Chinese population might have migrated and settled in Haenam-gun in Korea. Moreover, another northeast Chinese population might have migrated to Muan-gun in Korea though Sakhalin, Russia and Hokkaido, Japan. However, the possibility that the migratory locusts moved from northeast China might be isolated from each other in Korea, and that the Muan population might migrate to Japan cannot be excluded.

• Mycobiology
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• v.45 no.4
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• pp.297-311
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• 2017

Saprolegniasis is one of the most devastating oomycete diseases in freshwater fish which is caused by species in the genus Saprolegnia including Saprolegnia parasitica. In this study, we isolated the strain of S. parasitica from diseased rainbow trout in Korea. Morphological and molecular based identification confirmed that isolated oomycete belongs to the member of S. parasitica, supported by its typical features including cotton-like mycelium, zoospores and phylogenetic analysis with internal transcribed spacer region. Pathogenicity of isolated S. parasitica was developed in embryo, juvenile, and adult zebrafish as a disease model. Host-pathogen interaction in adult zebrafish was investigated at transcriptional level. Upon infection with S. parasitica, pathogen/antigen recognition and signaling (TLR2, TLR4b, TLR5b, NOD1, and major histocompatibility complex class I), pro/anti-inflammatory cytokines (interleukin $[IL]-1{\beta}$, tumor necrosis factor ${\alpha}$, IL-6, IL-8, interferon ${\gamma}$, IL-12, and IL-10), matrix metalloproteinase (MMP9 and MMP13), cell surface molecules ($CD8^+$ and $CD4^+$) and antioxidant enzymes (superoxide dismutase, catalase) related genes were differentially modulated at 3- and 12-hr post infection. As an anti-Saprolegnia agent, plant based lawsone was applied to investigate on the susceptibility of S. parasitica showing the minimum inhibitory concentration and percentage inhibition of radial growth as $200{\mu}g/mL$ and 31.8%, respectively. Moreover, natural lawsone changed the membrane permeability of S. parasitica mycelium and caused irreversible damage and disintegration to the cellular membranes of S. parasitica. Transcriptional responses of the genes of S. parasitica mycelium exposed to lawsone were altered, indicating that lawsone could be a potential anti-S. parasitica agent for controlling S. parasitica infection.

• Korean journal of food and cookery science
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• v.21 no.2 s.86
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• pp.163-170
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• 2005

Soybean is an important plant as the source of protein and oil, as well as phytochemicals such as genistien, daidzein, phenolic acids, phytic acid, tocopherol, and saponin. Chungkukjang, a fermented soybean paste, is common in Korean meals and bacillus is usually used in the fermentation of steamed soybean. For its processing, whole soybeans are boiled in water until the beans are soft, and then the drained beans are wrapped with rice straw or starter and set in a warm place at $65^{\circ}C\;for\;3\;\~\;4\;days$. Normally, the remaining cooked water which was drained from the steamed beans is discarded. We supposed that this water possesses hish amounts of useful components, and we therefore developed a modified method using the cooked water. After fermentation, we added the remaining cooked water which had been drained from the beans to the fermented soy beans and boiled them together. To investigate the bio-functionality of the modified Chungkukjang, the total antioxidative activity, isoflavones contents, phenolic acids, and 3-deoxyglucosone (3-DG) were measured at each stage of the preparation of chungkukjang. The original and modified chungkukjang possessed a high antioxidative activity compared with the other samples, as did the drained water after steaming of the soybean. The contents of genistein, daidzein, and phenolic acids, which contained antioxidative activity, were also increased in the original chungkukjang and their contents were similar in the modified chungkukjang. The content of 3-DG was increased in the modified chungkukjang compare with the original. It is suggested that the active soybean components delivered to the drained water during the steaming process were useful for increasing the bio-functionality of the modified chungkukjang.

• Korean journal of applied entomology
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• v.60 no.3
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• pp.287-304
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• 2021

Since 1995, researches on natural enemies have been conducted extensively in Korea. Research papers on natural enemies published in the Korean Journal of Applied Entomology from 1990 to 2020 were 130, which is 8.4% of all published papers during the same period. In 1990s, most research papers study the searching and biological characteristics of natural enemies, whereas the proportion of research papers related to the field application using the developed natural enemies has been increasing since 2010s. A total of 37 excellent natural enemies have been developed including 24 indigenous and 13 introduced natural enemies. In addition, 28 kinds of booklets and/or manuals were developed for field application of natural enemies. Although successes in research and development have been achieved since that period, more researches on search for and/or introduction of excellent natural enemy suitable for the Korean cultivation environment, mass production technology that can reduce cost, and quality control program in producing and distributing natural enemy remain to be pursued in the future. Furthermore, there is a need to develop the technology that can be used in compatible way with natural enemies and other crop protection agents including synthetic insecticides.