• Title/Summary/Keyword: Infection Mechanism

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Persistent Infection of Marine Birnavirus and its Status of Infection in Cells (잠복감염시의 해양버나바이러스의 세포내에서의 동태)

  • Jung, Sung-Ju;Oh, Myung-Joo
    • Journal of fish pathology
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    • v.15 no.1
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    • pp.9-16
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    • 2002
  • The objective of the study was to clarify the mechanism of persistent infection of marine birnavirus (MABV) in various nonpermissive cell lines. It was observed in CHSE-214, RTG-2 and RSBK-2 that the virus produced at high yield with typical cytopathic effect (CPE). On the contrary, the CPE was not produced in EPC, FHM and BF-2 cells. However amount of virus protein in both permissive and nonpermissive cell lines detected by ELISA was almost the same. Electron microscopy showed virions in permissive cells but not in nonpermissive cells. From the results, it is clear that virus protein and RNA were produced in nonpermissive cells as observed in permissive cells; however, assembly of the virus particles did not occur in nonpermissive cells.

H. pylori-associated Iron-Deficiency Anemia (Helicobacter pylori 관련 철분 결핍 빈혈)

  • Choe, Yon Ho
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.9 no.2
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    • pp.129-138
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    • 2006
  • Lots of cases relating Helicobacter pylori infection to iron-deficiency anemia have been described in the literature and H. pylori infection has emerged as a cause of refractory iron-deficiency anemia which is unresponsive to oral iron therapy. H. pylori-associated iron-deficiency anemia can be treated by H. pylori eradication. It is not thought to be attributable to gastrointestinal blood loss, such as duodenal ulcer. The mechanism by which H. pylori infection contributes to iron-deficiency anemia remains unclear. However, four possible explanations can be posited for this relationship; occult blood loss secondary to chronic gastritis, reduced iron absorption due to hypo- or achlorhydria, increased iron consumption by H. pylori, and iron sequestration in gastric mucosa. H. pylori-associated iron-deficiency anemia seems to develop in populations at increased risk for iron depletion. When pubescent girls, including athletes, are found to have iron-deficiency anemia refractory to iron administration, they should be evaluated for H. pylori infection.

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The Road to RNA Silencing is Paved with Plant-Virus Interactions

  • Palukaitis, Peter
    • The Plant Pathology Journal
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    • v.27 no.3
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    • pp.197-206
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    • 2011
  • RNA silencing has had a large impact on biology in general, as well as on our understanding of plant-pathogen interactions, especially interactions between plants and viruses. While most of what we know about the mechanism of RNA silencing was deduced in the last 12 years, many of the interactions between plants and viruses, as well as virus-virus interactions in plants, which we now know are manifestations of RNA silencing, were the subject of decades of work from numerous laboratories. These laboratories were examining the nature and extent of phenomena such as recovery from infection, the formation of dark green islands resistant to re-infection, synergy between unrelated viruses and cross-protection between related viruses, all first described in the late 1920s. In this review, the relationships between these phenomena and their place in the defense mechanism we call RNA silencing will be described, to show how they are all linked.

Development of Potato Virus Y Resistant Tobacco Plant by Transformation of the Untranslatable Viral Coat Protein Encoding cDNA (감자 바이러스 Y 비전이성 외피단백질 cDNA의 형질전환에 의한 바이러스 저항성 연초품종 개발)

  • 이청호;이영기;강신웅;박성원;김상석;박은경
    • Journal of the Korean Society of Tobacco Science
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    • v.19 no.2
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    • pp.117-123
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    • 1997
  • Viral coat protein (CP) encoding cDNA with artificial start and stop codons was synthesized by reverse-transcriptase polymerase chain reaction (RT-PCR) from the Korean isolate of potato virus Y-vein nectrosis strain (pVY-VN). To make PVY CP cDNA to untranslatable form, three stop codons were inserted near the start codon by "megaprimer-PCR" method. The untranslatable CP cDNA was subcloned to plant expression vector and transferred to N. tabacum cv. NC82 by Agrobacterium-mediated transformation. Highly resistant plants to PVY infection were screened, based on symptom development after mechanical virus inoculation. By genomic PCR and Southern blot analysis, one or more copies of the untranslatable CP gene were found in all transformants. From northern blot analysis, highly resistant transgenic lines had very low level of CP transcript but susceptible lines had high level, suggesting resistance to PVY infection should be related to RNA-mediated mechanism.mechanism.

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Genetic Factors, Viral Infection, Other Factors and Liver Cancer: An Update on Current Progress

  • Su, Cheng-Hao;Lin, Yong;Cai, Lin
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.9
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    • pp.4953-4960
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    • 2013
  • Primary liver cancer is one of the most common cancers at the global level, accounting for half of all cancers in some undeveloped countries. This disease tends to occur in livers damaged through alcohol abuse, or chronic infection with hepatitis B and C, on a background of cirrhosis. Various cancer-causing substances are associated with primary liver cancer, including certain pesticides and such chemicals as vinyl chloride and arsenic. The strong association between HBV infection and liver cancer is well documented in epidemiological studies. It is generally acknowledged that the virus is involved through long term chronic infection, frequently associated with cirrhosis, suggesting a nonspecific mechanism triggered by the immune response. Chronic inflammation of liver, continuous cell death, abnormal cell growth, would increase the occurrence rate of genetic alterations and risk of disease. However, the statistics indicated that only about one fifth of HBV carries would develop HCC in lifetime, suggesting that individual variation in genome would also influence the susceptibility of HCC. The goal of this review is to highlight present level of knowledge on the role of viral infection and genetic variation in the development of liver cancer.

Global Approaches to Identify Genes Involved during Infection Structure Formation in Rice Blast Fungus, Magnaporthe grisea

  • Park, Woo-Bong
    • The Plant Pathology Journal
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    • v.19 no.1
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    • pp.34-42
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    • 2003
  • The ascomycete Magnaporthe grisea is a pathogen of rice blast and is known to form specialized infection structures called appressoria for successful infection into host cells. To understand the molecular mechanism underlying infection process, appressorium-related genes were identified through global approaches including EST sequencing, differential hybridization, and sup-pression subtractive hybridization. EST database was generated on >2,000 cDNA clones randomly selected from appressorium stage cDNA library. Large number of ESTs showed homology to known proteins possibly involved in infection-related cellular development (attachment, germination, appressorium formation, and colonization) of rice blast fungus. The 1051 ESTs showing significant homology to known genes were assigned to 11 functional categories. Differential hybridization and suppression subtractive hybridization were applied to identify genes showing an appressorium stage specific expression pattern. A number of genes were selected as up-regulated during appressorium formation compared with the vegetative growing stage. Clones from various cDNA libraries constructed in different developmental stages were arrayed on slide glass for further expression profiling study. functional characterization of genes identified from these global approaches may lead to a better understand-ing of the infection process of this devastating plant disease, and the development of novel ways to protect host plant.

TLR4 Mediates Pneumolysin-Induced ATF3 Expression through the JNK/p38 Pathway in Streptococcus pneumoniae-Infected RAW 264.7 Cells

  • Nguyen, Cuong Thach;Kim, Eun-Hye;Luong, Truc Thanh;Pyo, Suhkneung;Rhee, Dong-Kwon
    • Molecules and Cells
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    • v.38 no.1
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    • pp.58-64
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    • 2015
  • Activating transcription factor-3 (ATF3) acts as a negative regulator of cytokine production during Gram-negative bacterial infection. A recent study reported that ATF3 provides protection from Streptococcus pneumoniae infection by activating cytokines. However, the mechanism by which S. pneumoniae induces ATF3 after infection is still unknown. In this study, we show that ATF3 was upregulated via Toll-like receptor (TLR) pathways in response to S. pneumoniae infection in vitro. Induction was mediated by TLR4 and TLR2, which are in the TLR family. The expression of ATF3 was induced by pneumolysin (PLY), a potent pneumococcal virulence factor, via the TLR4 pathway. Furthermore, ATF3 induction is mediated by p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK). Thus, this study reveals a potential role of PLY in modulating ATF3 expression, which is required for the regulation of immune responses against pneumococcal infection in macrophages.

Regulation of Innate Immune Response to Fungal Infection in Caenorhabditis elegans by SHN-1/SHANK

  • Sun, Lingmei;Li, Huirong;Zhao, Li;Liao, Kai
    • Journal of Microbiology and Biotechnology
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    • v.30 no.11
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    • pp.1626-1639
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    • 2020
  • In Caenorhabditis elegans, SHN-1 is the homologue of SHANK, a scaffolding protein. In this study, we determined the molecular basis for SHN-1/SHANK in the regulation of innate immune response to fungal infection. Mutation of shn-1 increased the susceptibility to Candida albicans infection and suppressed the innate immune response. After C. albicans infection for 6, 12, or 24 h, both transcriptional expression of shn-1 and SHN-1::GFP expression were increased, implying that the activated SHN-1 may mediate a protection mechanism for C. elegans against the adverse effects from fungal infection. SHN-1 acted in both the neurons and the intestine to regulate the innate immune response to fungal infection. In the neurons, GLR-1, an AMPA ionotropic glutamate receptor, was identified as the downstream target in the regulation of innate immune response to fungal infection. GLR-1 further positively affected the function of SER-7-mediated serotonin signaling and antagonized the function of DAT-1-mediated dopamine signaling in the regulation of innate immune response to fungal infection. Our study suggests the novel function of SHN-1/SHANK in the regulation of innate immune response to fungal infection. Moreover, our results also denote the crucial role of neurotransmitter signals in mediating the function of SHN-1/SHANK in regulating innate immune response to fungal infection.

Effect of respiratory syncytial virus on the growth of hepatocellular carcinoma cell-lines

  • Choi, Song Hee;Park, Byoung Kwon;Lee, Keun-Wook;Chang, Jun;Lee, Younghee;Kwon, Hyung-Joo
    • BMB Reports
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    • v.48 no.10
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    • pp.565-570
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    • 2015
  • In several reports, the respiratory syncytial virus (RSV) was identified as an oncolytic virus in cancer cells (e.g., lung and prostate cancer). However, the effects of RSV in hepatocellular carcinoma (HCC) cells have not yet been investigated. Here, we observed the inhibitory effects of RSV infection in HCC cell-lines. Cell growth was significantly decreased by RSV infection in BNL-HCC, Hep3B, Huh-7 and SNU-739 cells. After RSV infection, plaque formation and syncytial formation were observed in affected Hep3B and Huh-7 cells. RSV protein-expression was also detected in Hep3B and Huh-7 cells; however, only Huh-7 cells showed apoptosis after RSV infection. Furthermore, inhibition of cell migration by RSV infection was observed in BNL-HCC, Hep3B, Huh-7 and SNU-739 cells. Therefore, further investigation is required to clarify the molecular mechanism of RSV-mediated inhibition of HCC cell growth, and to develop potential RSV oncolytic viro-therapeutics.

Factors affecting complications after treatment of epidermal cyst

  • Choi, Man Ki;Chung, Kyu Jin
    • Journal of Yeungnam Medical Science
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    • v.36 no.2
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    • pp.136-140
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    • 2019
  • Background: Epidermal cysts are the most common benign epithelial tumors in humans. The curative treatment of epidermal cyst is surgical excision. However, only few studies have investigated the cause and mechanism of postoperative complications of epidermal cysts. Therefore, this study aimed to evaluate the factors affecting complications of epidermal cyst after surgical treatment. Methods: Patients with histologically diagnosed epidermal cysts were selected from among 98 consecutive patients with excised benign cystic tumors from March 2014 to August 2017. Sex, age, size, mobility, site of occurrence, history of infection, history of incision and drainage, complications, history of reoperation, and method of overcoming complications was obtained by analyzing medical records retrospectively. Results: Five of the 98 patients had wound dehiscence due to surgical infection. Three of them underwent wound healing with conservative treatment without a second operation. The other two patients underwent a second operation and showed signs of preoperative infection. None of the factors showed statistical significance in relation to the occurrence of complications. Conclusion: Postoperative complications occurred when the excision of the epidermal cyst was performed at preoperative infection sites or at sites with high tension, so attention should be paid to postoperative care.