• Journal of Microbiology and Biotechnology
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• v.24 no.12
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• pp.1609-1621
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• 2014

The plant pathogen Burkholderia gladioli, which has a broad host range that includes rice and onion, causes bacterial panicle blight and sheath rot. Based on the complete genome sequence of B. gladioli BSR3 isolated from infected rice sheaths, the genome of B. gladioli BSR3 contains the luxI/luxR family of genes. Members of this family encode N-acyl-homoserine lactone (AHL) quorum sensing (QS) signal synthase and the LuxR-family AHL signal receptor, which are similar to B. glumae BGR1. In B. glumae, QS has been shown to play pivotal roles in many bacterial behaviors. In this study, we compared the QS-dependent gene expression between B. gladioli BSR3 and a QS-defective B. gladioli BSR3 mutant in two different culture states (10 and 24 h after incubation, corresponding to an exponential phase and a stationary phase) using RNA sequencing (RNA-seq). RNA-seq analyses including gene ontology and pathway enrichment revealed that the B. gladioli BSR3 QS system regulates genes related to motility, toxin production, and oxalogenesis, which were previously reported in B. glumae. Moreover, the uncharacterized polyketide biosynthesis is activated by QS, which was not detected in B. glumae. Thus, we observed not only common QS-dependent genes between B. glumae BGR1 and B. gladioli BSR3, but also unique QS-dependent genes in B. gladioli BSR3.

• Molecules and Cells
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• v.20 no.2
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• pp.241-246
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• 2005

PDK-1 activates PI3-kinase/Akt signaling and regulates fundamental cellular functions, such as growth and survival. NF-${\kappa}B$ is involved in the induction of a variety of cellular genes affecting immunity, inflammation and the resistance to apoptosis induced by some anti-cancer drugs. Even though the crucial involvement of the PI3-kinase/Akt pathway in the anti-apoptotic activation of NF-${\kappa}B$ is well known, the exact role of PDK-1 as well as PI3-kinase/Akt in NF-vactivation is not understood. Here we demonstrate that PDK-1 plays a pivotal role in transcriptional activation of NF-${\kappa}B$ by dissociating the transcriptional co-repressor HDAC1 from the p65 subunit of NF-${\kappa}B$. The association of CBP with p65 was not directly modulated by PDK-1 or by PI3-kinase. Etoposide activated NF-${\kappa}B$ through PI3-kinase/Akt, and the transcription activation domain (TAD) of p65 was further activated by wild-type PDK-1. Overexpression of a dominant negative PDK-1 mutant decreased etoposide-induced NF-${\kappa}B$ transcription and further down-regulated the ectopic HDAC1-mediated decrease in NF-${\kappa}B$ transcriptional activity. Thus activation of PDK-1 relieves the HDAC1-mediated repression of NF-${\kappa}B$ that may be related to basal as well as activated transcription by NF-${\kappa}B$. This effect may also explain the role of the PI3-kinase/PDK-1 pathway in the anti-apoptotic function of NF-${\kappa}B$ associated with the chemoresistance of cancer cells.

• Molecules and Cells
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• v.39 no.3
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• pp.258-265
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• 2016

In metastatic breast cancer, the acquisition of malignant traits has been associated with the increased rate of cell growth and division, mobility, resistance to chemotherapy, and invasiveness. While screening for the key regulators of cancer metastasis, we observed that neurotrophin receptor TrkB is frequently overexpressed in breast cancer patients and breast cancer cell lines. Additionally, we demonstrate that TrkB expression and clinical breast tumor pathological phenotypes show significant correlation. Moreover, TrkB expression was significantly upregulated in basal-like, claudin-low, and metaplastic breast cancers from a published microarray database and in patients with triple-negative breast cancer, which is associated with a higher risk of invasive recurrence. Interestingly, we identified a new TrkB-regulated functional network that is important for the tumorigenicity and metastasis of breast cancer. We demonstrated that TrkB plays a key role in regulation of the tumor suppressors Runx3 and Keap1. A markedly increased expression of Runx3 and Keap1 was observed upon knockdown of TrkB, treatment with a TrkB inhibitor, and in TrkB kinase dead mutants. Additionally, the inhibition of PI3K/AKT activation significantly induced Runx3 and Keap1 expression. Furthermore, we showed that TrkB enhances metastatic potential and induces proliferation. These observations suggest that TrkB plays a key role in tumorigenicity and metastasis of breast cancer cells through suppression of Runx3 or Keap1 and that it is a promising target for future intervention strategies for preventing tumor metastasis and cancer chemoprevention.

• BMB Reports
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• v.40 no.6
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• pp.1083-1089
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• 2007

The HAP complex has been found in many eukaryotic organisms. HAP recognizes the CCAAT box present in the promoters of 30% of all eukaryotic genes. The HAP complex consists of three subunits - HAP2, HAP3 and HAP5. In this paper, we report the biological function of the AtHAP3b gene that encodes one of the HAP3 subunits in Arabidopsis. Compared with wild-type plants, hap3b-1 and hap3b-2 mutants exhibited a delayed flowering time under long-day photoperiod conditions. Moreover, the transcription levels of FT were substantially lower in the mutants than in the wild-type plants. These results imply that AtHAP3b may function in the control of flowering time by regulating the expression of FT in Arabidopsis. In a subsequent study, AtHAP3b was found to be induced by osmotic stress. Under osmotic stress conditions, the hap3b- 1 and hap3b-2 mutants flowered considerably later than the wild-type plants. These results suggest that the AtHAP3b gene plays more important roles in the control of flowering under osmotic stress in Arabidopsis.

• Korean Journal of Microbiology
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• v.55 no.2
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• pp.112-116
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• 2019

Thp1/PCID2 is a subunit of the evolutionally conserved TREX-2 complex, which is required for transcription-coupled mRNA export from the nucleus to the cytoplasm. In fission yeast, Schizosaccharomyces pombe, there are two orthologs of the Thp1/PCID2 protein. In addition to pci2 (SPBC1105.07c) gene, SPAC1B3.08 gene encodes a PCI domain-containing protein that is predicted as a component of TREX-2 complex. Overexpression of SPAC1B3.08 cause slight defects of both growth and mRNA export. Yeast two-hybrid and co-immunoprecipitation analysis exhibits that the SPAC1B3.08 protein interacted with Sac3 and Dss1, which are another components of TREX-2 complex. These observations support the possibility that the S. pombe SPAC1B3.08 protein, as a component of TREX-2 complex, is involved in mRNA export.

• The Korean Journal of Ecology
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• v.27 no.2
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• pp.93-98
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• 2004

Decay rate and nutrient dynamics during decomposition of oak (Quercus acutissima) branches were investigated for 33-months in Kongju, Korea. After 33-months, remaining weight of B₁, B₂ and B₃ was 44.5%, 58.5% and 55.37%, respectively. Decomposition constant (k) for B₁, B₂ and B₃ was 0.294/yr, 0.195/yr, 0.215/yr, respectively. N concentration in decomposing oak branches increased in all diameter classes. After 33-months, remaining N in B₁, B₂ and B₃ was 101.2%, 91.9%, 104.4%, respectively. P concentration in decomposing oak branches increased in B₁ and B₂, and there was no immobilization period. After 33-months, remaining P in B₁, B₂ and B₃ was 57.2%, 74.4%, 53.9%, respectively. K concentration in decomposing oak branches decreased significantly. Remaining K in B₁, B₂ and B₃ was 7.7%, 17.1% and 17.2%, respectively, which was significantly lower than other nutrients. Ca concentration in decomposing oak branches increased in B₂ and B₃. After 33-months, remaining Ca in B₁, B₂ and B₃ was 58.5%, 47.8% and 75.2%, respectively. Initial concentration of Mg in oak branch was higher in smaller diameter class. After 33-months, remaining Mg in B₁, B₂ and B₃ was 44.3%, 57.9% and 47.7%, respectively.

• The Journal of the Acoustical Society of Korea
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• v.27 no.2
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• pp.57-65
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• 2008

Setting parameters of Ultrasonic scanners influence the quality of ultrasonic images. In order to obtain optimized images sonographers need to understand the effects of the setting parameters on ultrasonic images. The present study considered typical four parameters including TGC (Time Gain Control), Gain, Frequency, DR (Dynamic Range). LCS (low contrast sensitivity) was chosen to quantitatively compare the quality of the images. In the present experiment LCS targets of a standard ultrasonic test phantom (539, ATS, USA) were imaged using a clinical ultrasonic scanner (SA-9000 PRIME, Medison, Korea). Altering the settings in the parameters of the ultrasonic scanner, 6 LCS target images (+15 dB, +6 dB, +3 dB, -3 dB, -6 dB, -15 dB) to each setting were obtained, and their LCS values were calculated. The results show that the mean pixel value (LCS) is the highest at the max setting in TGC, mid to max in gain and pen mode in frequency and 40-66 dB in DR. Among all images, the image being the highest in LCS was obtained at the setting of DR 40 dB. It is expected that the results will be of use in setting the parameters when ultrasonically examining masses often clinically found In either solid lesions (similar to +15, +6, +3 dB targets) or cystic lesions (similar to -15, -6, -3 dB targets).

• Journal of the Korean Chemical Society
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• v.49 no.2
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• pp.173-181
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• 2005

• Journal of the Korean Chemical Society
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• v.49 no.4
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• pp.389-398
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• 2005

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2001.11a
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• pp.180-183
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• 2001

본 논문에서는 N개의 평행 결합선로를 이용한 3dB 결합기를 해석하였으며, 유도된 식에 의하여 최소의 단수와 크기로 3dB 결합기를 설계하였다. 기존의 Spectral Domain상에서 N단 평행 결합선로의 복잡한 관계식 유도를 S 파라미터 관계식으로 간단히 유도 하였으며, 유도된 식의 타당성을 위해 실제 제작 검증하였다. 제작된 결합기는 Loose coupling의 평행 결합 선로의 광대역 특성을 그대로 이용하기 때문에 Lange Coupler와 같은 높은 임피던스와 Tight coupling을 구현 할 필요가 없으며, wire bonding도 용이하게 된다. 최소의 단수로 구현하기 위해 RT/Duroid의 R06006과 같은 높은 유전율과 두꺼운 기판을 사용하여 2단으로 3dB 구현이 가능하게 하였다. 제작결과 3.6GHz에서5.5GHz로 대략 42%(0.5dB imbalance) 정도의 광대역특성을 가지고 위상오차도 1$^{\circ}$내외의 결합기를 구현할 수 있었고 격리도 특성 또한 대역 내에서 15dB 내외의 특성을 보였다.