• Title/Summary/Keyword: host factor

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What Makes Red Quasars Red?

  • Kim, Dohyeong;Im, Myungshin
    • The Bulletin of The Korean Astronomical Society
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    • v.41 no.1
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    • pp.66.2-66.2
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    • 2016
  • Red quasars have been suspected to be an intermediate population between merger-driven star-forming galaxies and normal quasars. In this scenario, red quasars are expected to have dusty red color coming from the dust extinction by dust and gas in their host galaxy. However, several studies have proposed different explanation of the red color of red quasars, which are i) a moderate viewing angle between type 1 and 2 quasars, ii) an unusual covering factor of dust torus, and iii) an anomalous synchrotron emission with a peak at NIR wavelength. In this study, we investigate the factor leading to the red color of red quasars by using the line luminosity ratios of the hydrogen Balmer to Paschen series of 11 red quasars. We find the Pb/Hb luminosity ratios of the red quasars are significantly higher than those of normal quasars. Moreover, we compare the Pb/Hb luminosity ratios of the red quasars to the theoretically expected line luminosity ratios computed from the CLOUDY code. We find the line luminosity ratios of the red quasars cannot be explained by the theoretical line luminosity ratios with any physical conditions. We conclude that red color of red quasars comes from dust extinction by their host galaxy. This result is consistent with the picture that red quasars are an intermediate population between the merger-driven star-forming galaxies and normal quasars.

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MiT Family Transcriptional Factors in Immune Cell Functions

  • Kim, Seongryong;Song, Hyun-Sup;Yu, Jihyun;Kim, You-Me
    • Molecules and Cells
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    • v.44 no.5
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    • pp.342-355
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    • 2021
  • The microphthalmia-associated transcription factor family (MiT family) proteins are evolutionarily conserved transcription factors that perform many essential biological functions. In mammals, the MiT family consists of MITF (microphthalmia-associated transcription factor or melanocyte-inducing transcription factor), TFEB (transcription factor EB), TFE3 (transcription factor E3), and TFEC (transcription factor EC). These transcriptional factors belong to the basic helix-loop-helix-leucine zipper (bHLH-LZ) transcription factor family and bind the E-box DNA motifs in the promoter regions of target genes to enhance transcription. The best studied functions of MiT proteins include lysosome biogenesis and autophagy induction. In addition, they modulate cellular metabolism, mitochondria dynamics, and various stress responses. The control of nuclear localization via phosphorylation and dephosphorylation serves as the primary regulatory mechanism for MiT family proteins, and several kinases and phosphatases have been identified to directly determine the transcriptional activities of MiT proteins. In different immune cell types, each MiT family member is shown to play distinct or redundant roles and we expect that there is far more to learn about their functions and regulatory mechanisms in host defense and inflammatory responses.

Evidence of hydrolyzed traditional Korean red ginseng by malted barley on activation of receptor interacting proteins 2 and IkappaB kinase-beta in mouse peritoneal macrophages

  • Rim, Hong-Kun;Kim, Kyu-Yeob;Moon, Phil-Dong
    • CELLMED
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    • v.2 no.3
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    • pp.27.1-27.6
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    • 2012
  • Red ginseng, which has a variety of biological and pharmacological activities including antioxidant, anti-inflammatory, antimutagenic and anticarcinogenic effects, has been used for thousands of years as a general tonic in traditional oriental medicine. Here, we tested the immune regulatory activities of hydrolyzed red ginseng by malted barley (HRG) on the expressions of receptor interacting proteins (Rip) 2 and $I{\kappa}B$ kinase-beta (IKK-${\beta}$) in mouse peritoneal macrophages. We show that HRG increased the activations of Rip 2 and IKK-${\beta}$ for the first time. When HRG was used in combination with recombinant interferon-${\gamma}$ (rIFN-${\gamma}$), there was a marked cooperative induction of nitric oxide (NO) production. The increased expression of inducible NO synthase from rIFN-${\gamma}$ plus HRG-stimulated cells was almost completely inhibited by pre-treatment with pyrrolidine dithiocarbamate (PDTC), an inhibitor of nuclear factor-${\kappa}B$ (NF-${\kappa}B$). In addition, the treatment of peritoneal macrophages with rIFN-${\gamma}$ plus HRG caused significant increases in tumor necrosis factor (TNF)-${\alpha}$ mRNA expression and production. Because NO and TNF-${\alpha}$ play an important role in the immune function and host defense, HRG treatment can modulate several aspects of the host defense mechanisms as a result of the stimulations of the inducible nitric oxide synthase and NF-${\kappa}B$. In conclusion, our findings demonstrate that HRG increases the productions of NO and TNF-${\alpha}$ from rIFN-${\gamma}$-primed macrophages and suggest that Rip2/IKK-${\beta}$ plays a critical role in mediating these immune regulatory effects of HRG.

Inprovement of Handoff Protocol for Real-Time Packet Transmission in Cellular Wireless Networks (셀룰라 무선 망에서 실시간 패킷 전송을 위한 핸드오프 프로토콜 개선)

  • Han, Seung-Jin;Lee, Jung-Hyun
    • The Transactions of the Korea Information Processing Society
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    • v.7 no.11S
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    • pp.3675-3683
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    • 2000
  • The Handoff is the core technical factor that is required when mobile host moves from one area to another, while transmitting and receiving data. The existing works try to minimize the loss of pockets by forwarding packets to the Cell which a mobile host will move to. However, though the loss quantity is little, the accumulated loss can del(rade the performance of the TCP, and can be a serious problem if data is sensitive to the loss of packets. In this paper, we can reduce a memory requesting in FA by restricting the mobile host to move within at most 2 movable cells and design the improved handoff protocol for Mil to receive packets seamlessly in spite of handoff. We can evaluate that the suggested method is superior to the previous method, as a result of comparing with it.

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Nonstructural Protein of Severe Fever with Thrombocytopenia Syndrome Phlebovirus Inhibits TBK1 to Evade Interferon-Mediated Response

  • Lee, Jae Kyung;Shin, Ok Sarah
    • Journal of Microbiology and Biotechnology
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    • v.31 no.2
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    • pp.226-232
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    • 2021
  • Severe fever with thrombocytopenia syndrome virus (SFTSV) is an emerging phlebovirus of the Phenuiviridae family that has been circulating in the following Asian countries: Vietnam, Myanmar, Taiwan, China, Japan, and South Korea. Despite the increasing infection rates and relatively high mortality rate, there is limited information available regarding SFTSV pathogenesis. In addition, there are currently no vaccines or effective antiviral treatments available. Previous reports have shown that SFTSV suppresses the host immune response and its nonstructural proteins (NSs) function as an antagonist of type I interferon (IFN), whose induction is an essential part of the host defense system against viral infections. Given that SFTSV NSs suppress the innate immune response by inhibiting type I IFN, we investigated the mechanism utilized by SFTSV NSs to evade IFNmediated response. Our co-immunoprecipitation data suggest the interactions between NSs and retinoic acid inducible gene-I (RIG-I) or TANK binding kinase 1 (TBK1). Furthermore, confocal analysis indicates the ability of NSs to sequester RIG-I and related downstream molecules in the cytoplasmic structures called inclusion bodies (IBs). NSs are also capable of inhibiting TBK1-interferon regulatory factor 3 (IRF3) interaction, and therefore prevent the phosphorylation and nuclear translocation of IRF3 for the induction of type I IFN. The ability of SFTSV NSs to interact with and sequester TBK1 and IRF3 in IBs demonstrate an effective yet unique method utilized by SFTSV to evade and suppress host immunity.

The Crucial Role of Chloroplast-Related Proteins in Viral Genome Replication and Host Defense against Positive-Sense Single-Stranded RNA Viruses

  • John, Bwalya;Kook-Hyung, Kim
    • The Plant Pathology Journal
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    • v.39 no.1
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    • pp.28-38
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    • 2023
  • Plant viruses are responsible for worldwide production losses of numerous economically important crops. The most common plant RNA viruses are positivesense single-stranded RNA viruses [(+)ss RNA viruses]. These viruses have small genomes that encode a limited number of proteins. The viruses depend on their host's machinery for the replication of their RNA genome, assembly, movement, and attraction to the vectors for dispersal. Recently researchers have reported that chloroplast proteins are crucial for replicating (+)ss plant RNA viruses. Some chloroplast proteins, including translation initiation factor [eIF(iso)4E] and 75 DEAD-box RNA helicase RH8, help viruses fulfill their infection cycle in plants. In contrast, other chloroplast proteins such as PAP2.1, PSaC, and ATPsyn-α play active roles in plant defense against viruses. This is also consistent with the idea that reactive oxygen species, salicylic acid, jasmonic acid, and abscisic acid are produced in chloroplast. However, knowledge of molecular mechanisms and functions underlying these chloroplast host factors during the virus infection is still scarce and remains largely unknown. Our review briefly summarizes the latest knowledge regarding the possible role of chloroplast in plant virus replication, emphasizing chloroplast-related proteins. We have highlighted current advances regarding chloroplast-related proteins' role in replicating plant (+)ss RNA viruses.

Gene Expression and Secretion of Human Epidermal Growth Factor in a Methylotrophic Yeast Hansenula polymorpha (메나놀 자화 효모 Hansenula polymorpha를 이용한 재조합 인체 표피 성장인자 유전자의 발현 및 분비)

  • Oh, Yong-Ik;Sohn, Jung-Hoon;Choi, Eui-Sung;Kim, Hee-Chul;Rhee, Sang-Ki
    • Microbiology and Biotechnology Letters
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    • v.22 no.5
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    • pp.477-484
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    • 1994
  • Using a methylotrophic yeast Hansenula polymorpha, a heterologous gene expression and secretion system was developed for the production of hEGF(human Epidermal Growth Factor) which has been shown to promote epithelial cell proliferation and to inhibit gastric acid secretion. The hEGF gene was chemically synthesized according to the preferred codon usage in H. polymor- pha and expressed under the control of the strong and inducible methanol oxidase(MOX) promoter. The mating factor $\alpha$ pre-pro leader sequence of Saccharomyces cerevisiae was employed for hEGF to be secreted into the extracellular medium. This expression cassette was stably integrated into the host chromosomal DNA. Mature hEGF was efficiently expressed and secreted into the extracel- lular medium. About 24 mg/l of hEGF was detected in the cuture supernatant of a transformant with pA-EGF3 under the suboptimal culture conditions.

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Improved EL efficiency and operational lifetime of top-emitting white OLED with a co-doping technology

  • Lee, Meng-Ting;Tseng, Mei-Rurng
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08b
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    • pp.1411-1414
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    • 2007
  • We have developed a top-emitting white organic electroluminescent device (TWOLED) incorporating a low-reflectivity molybdenum (Mo) anode and doped transport layers as well as a dual-layer architecture of doped blue and yellow emitters with the same blue host. The EL efficiency and operational lifetime of TWOLED can be enhanced by a factor of 1.2 and 3.4 than that of standard TWOLED, respectively, with a co-doping technology in yellow emitter by doping another blue dopant. The enhancement in device performances can be attributed to improve the energy transfer efficiency from blue host to yellow dopant through a blue dopant as medium in yellow emitter.

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Noneffective Results of Steinernematid and Hoterorhabditid Nematodes Agains Pill bug, Armadillidium vulgare (Isopoda : Armadillidae) (Steinernematid와 Heterorhabditid 선충의 쥐며느리에 대한 비효용적결과)

  • 추호렬;이동운;허은영;김준범
    • Korean journal of applied entomology
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    • v.35 no.1
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    • pp.91-93
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    • 1996
  • Steinemematid and heterorhabditid nematodes were not effective to control the piU bug, Armadillidium vulgare although these nematodes were able to infect pill bugs. Steinernema carpocapsae Pocheon strain and S. glaseri Dongrae strain were more effective than S. carpocapsae AU strain or Heterorhabditis bacteriophora. Nematode concentration was more important factor than host density to develop infectivity.

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Prevention of Macrophage-Related Inflammatory Diseases by Allergina

  • Han, Sang-B.;Lee, Chang-W.;Park, Song-K.;Yoon, Won-K.;Moon, Jae-S.;Lee, Ki-H.;Kim, Hyung-C.;Kim, Hwan-M.
    • Archives of Pharmacal Research
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    • v.26 no.4
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    • pp.312-316
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    • 2003
  • The oriental herbal combination allergina has been shown to inhibit allergic inflammation. In the present study, we demonstrate that the oral administration of allergina markedly inhibits the progression of inflammatory diseases, such as graft-versus-host diseases (in the allogeneic bone marrow transplantation and the parent-into-F1 transplantation models), collagen-induced arthritis and sheep red blood cell-induced delayed type hypersensitivity. The immunosuppressive activity of allergina in vivo appears to be associated, at least in part, with the inhibition of tumor necrosis factor-a production. In conclusion, our results suggest that allergina could be useful as a immunosuppressive agent for the treatment of macrophage-related inflammatory disease.