• Journal of Microbiology and Biotechnology
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• v.27 no.10
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• pp.1837-1843
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• 2017

Knowledge of avian host responses to brucellosis is critical to understanding how birds resist this infection; however, this mechanism is not well established. On the other hand, temperature has a major involvement in the physiology of living organisms, and cell death induced by heat is attributed to protein denaturation. This study demonstrates the direct bactericidal effect of a high temperature ($41^{\circ}C$) on Brucella abortus that resulted in the gradual reduction of intracellular bacteria and inhibited bacterial growth within avian macrophage HD11 in an increasing period of time. On the other hand, this study also revealed that high temperature does not affect the rate of bacterial uptake, as confirmed by the bacterial adherence assay. No significant difference was observed in the expression of target genes between infected and uninfected cells for both temperatures. This study suggests the susceptibility of B. abortus to bacterial death under a high temperature with an increased period of incubation, leading to suppression of bacterial growth.

• The Journal of the Korean Society for Microbiology
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• v.34 no.5
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• pp.435-443
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• 1999

Orientia tsutsugamushi is obligate intracellular bacterium that grows within the cytoplasm of the eukaryotic host cells. Therefore capability of the attachment, entry into the host cell and intracellular survival should be critical process for oriential infection. In this study we investigated the cellular invasion mechanism of Orientia tsutsugamushi and the role of transmembrane heparan sulfate proteoglycan, which binds diverse components at the cellular microenvironment and is implicated as host cell receptors for a variety of microbial pathogens. First of all Orientia tsutsugamushi can invade a wide range of nonprofessional phagocytic cells including fibroblast, epithelial cells and endothelial cells of various host species, including Band T lymphocytes. Thus, it was postulated that the attachment of O. tsutsugamushi requires the recognition of ubiquitous surface structures of many kinds of host cells. Treatments with heparan sulfate and heparin inhibited the infection of Orientia tsutsugamushi in dose-dependent manner for L cell, mouse fibroblast, whereas other glycosaminoglycans such as chondroitin sulfate had no effect. Collectively, these findings provide strong evidence that initial interaction with heparan sulfate proteoglycan is required for the oriential invasion into host cells.

• Clinical and Experimental Pediatrics
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• v.49 no.10
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• pp.1116-1119
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• 2006

Pyomyositis is a primary bacterial infection of the skeletal muscles. Although infection can affect any skeletal muscle, the large muscle groups such as the quadriceps or gluteal muscles are most often the focus of this disease, and most commonly the inflammation is focal, involving a single muscle. The mechanism of pyomyositis is poorly understood. The local mechanical trauma at the time of an incidental bacteremia is frequently postulated as a mechanism that could explain the high incidence of the disease in tropical areas and its male preponderance. Staphylococcus aureus is the most common organism responsible for pyomyositis. Mycobacterium tuberculosis primarily affects the lungs, and the prevalence of active pulmonary tuberculosis co-existing with musculoskeletal tuberculosis has been about 30 percent. We report here on a case of an otherwise healthy 17-month-old girl, who had tuberculous pyomyositis at the upper arm after the hepatitis A vaccination with no evidence of any coexistent active tuberculosis.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.5
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• pp.517-521
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• 2008

A worm is a malware that propagates quickly from host to host without any human intervention. Need of early worm detection has changed research paradigm from signature based worm detection to the behavioral based detection. To increase effectiveness of proposed solution, in this paper we present mechanism of detection and prevention of worm in distributed fashion. Furthermore, to minimize the worm destruction; upon worm detection we propagate the possible attack aleγt to neighboring nodes in secure and organized manner. Considering worm behavior, our proposed mechanism detects worm cycles and infection chains to detect the sudden change in network performance. And our model neither needs to maintain a huge database of signatures nor needs to have too much computing power, that is why it is very light and simple. So, our proposed scheme is suitable for the ubiquitous environment. Simulation results illustrate better detection and prevention which leads to the reduction of infection rate.

• Molecules and Cells
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• v.38 no.2
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• pp.122-129
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• 2015

DBM-2198, a six-membered azasugar nucleotide (6-AZN)-containing phosphorothioate (P = S) oligonucleotide (AZPSON), was described in our previous publication [Lee et al. (2005)] with regard to its antiviral activity against a broad spectrum of HIV-1 variants. This report describes the mechanisms underlying the anti-HIV-1 properties of DBM-2198. The LTR-mediated reporter assay indicated that the anti-HIV-1 activity of DBM-2198 is attributed to an extracellular mode of action rather than intracellular sequence-specific antisense activity. Nevertheless, the antiviral properties of DBM-2198 and other AZPSONs were highly restricted to HIV-1. Unlike other P = S oligonucleotides, DBM-2198 caused no host cell activation upon administration to cultures. HIV-1 that was pre-incubated with DBM-2198 did not show any infectivity towards host cells whereas host cells pre-incubated with DBM-2198 remained susceptible to HIV-1 infection, suggesting that DBM-2198 acts on the virus particle rather than cell surface molecules in the inhibition of HIV-1 infection. Competition assays for binding to HIV-1 envelope protein with anti-gp120 and anti-V3 antibodies revealed that DBM-2198 acts on the viral attachment site of HIV-1 gp120, but not on the V3 region. This report provides a better understanding of the antiviral mechanism of DBM-2198 and may contribute to the development of a potential therapeutic drug against a broad spectrum of HIV-1 variants.

• The Plant Pathology Journal
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• v.33 no.4
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• pp.370-381
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• 2017

Rathayibacter tritici, which is a Gram positive, plant pathogenic, non-motile, and rod-shaped bacterium, causes spike blight in wheat and barley. For successful pathogenesis, R. tritici is associated with Anguina tritici, a nematode, which produces seed galls (ear cockles) in certain plant varieties and facilitates spread of infection. Despite significant efforts, little research is available on the mechanism of disease or bacteria-nematode association of this bacterium due to lack of genomic information. Here, we report the first complete genome sequence of R. tritici NCPPB 1953 with diverse features of this strain. The whole genome consists of one circular chromosome of 3,354,681 bp with a GC content of 69.48%. A total of 2,979 genes were predicted, comprising 2,866 protein coding genes and 49 RNA genes. The comparative genomic analyses between R. tritici NCPPB 1953 and R. toxicus strains identified 1,052 specific genes in R. tritici NCPPB 1953. Using the BlastKOALA database, we revealed that the flexible genome of R. tritici NCPPB 1953 is highly enriched in 'Environmental Information Processing' system and metabolic processes for diverse substrates. Furthermore, many specific genes of R. tritici NCPPB 1953 are distributed in substrate-binding proteins for extracellular signals including saccharides, lipids, phosphates, amino acids and metallic cations. These data provides clues on rapid and stable colonization of R. tritici for disease mechanism and nematode association.

• Korean Journal of Veterinary Service
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• v.27 no.4
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• pp.355-369
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• 2004

The equine herpesvirus type 1 (EHV-1) immediate-early (IE) protein is a potent transactivator responsible for the activation of both early and late genes during the course of infection and is comprised of discrete functional domains that mediate its many functions. Interaction between trans activators such as the IE protein and various components of the RNA polymerase II transcription initiation machinery has been demonstrated to be critical for transactivation. In the present report, it is addressed the hypothesis that the IE protein interacts with various components of transcription machinery to mediate transactivation of target viral genes. In these studies, it is demonstrated that in vitro transcribed and translated IE protein interacts with TFIIB-agarose conjugate but not with TFIID-agarose conjugate. Additional immunoprecipitation studies using nuclear extracts derived from EHV-1 infected RK-13 cells confirmed that the IE protein interacts strongly with TFIIB, but fails to interact with TFIID. IR2, a truncated form of the IE protein lacking the potent transactivation domain and involved in the down-regulation of the IE gene, also interacted with TFIIB but not with TFIID. Studies were also performed to ascertain if particular TBP-associated factors (TAFs) could mediate IE or IR2 binding to TFIID. In vitro transcribed and translated TAF250 added to nuclear extracts generated from EHV-1 infected cells also failed to mediate an interaction between the IE protein or the IR2 protein and TFIID. This study demonstrated that the IE protein mediates transactivation of target viral genes by a mechanism that involves TFIIB. This is in contrast to mechanisms that have been proposed for both the herpes simplex virus ICP4 and VP16 protein which have been proposed to transactivate viral genes through interactions involving both TFIIB and TFIID. This study also intimates that IR2 mediate its repressive effects during the course of EHV-1 infection by a mechanism that involves sequestration of various transcription factors.

• BMB Reports
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• v.39 no.1
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• pp.9-15
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• 2006

To prove whether error catastrophe /lethal mutagenesis is the primary antiviral mechanism of action of ribavirin against foot-and-mouth disease virus (FMDV). Ribavirin passage experiments were performed and supernatants of $Rp_1$ to $Rp_5$ were harvested. Morphological alterations as well as the levels of viral RNAs, proteins, and infectious particles in the BHK-21 cells infected using the supernatants of $Rp_1$ to $Rp_5$ and control were measured by microscope, real-time RT-PCR, western-blotting and plaque assays, respectively. The mutation frequency was measured by sequencing the complete P1- and 3D-encoding region of FMDV after a single round of virus infection from ribavirin-treated or untreated FMDV-infected cells. Ribavirin treatment for FMDV caused dramatically inhibition of multiplication in cell cultures. The levels of viral RNAs, proteins, and infectious particles in the BHK-21 cells infected were more greatly reduced along with the passage from $Rp_1$ to $Rp_5$, moreover, nucleocapsid protein could not be detected and no recovery of infectious virus in the supernatant or detection of intracellular viral RNA was observed at the $Rp_5$-infected cells. A high mutation rate, giving rise to an 8-and 11-fold increase in mutagenesis and resulting in some amino acid substitutions, was found in viral RNA synthesized at a single round of virus infection in the presence of ribavirin of $1000\;{\mu}M$ and caused a 99.7% loss in viral infectivity in contrast with parallel untreated control virus. These results suggest that the antiviral molecular mechanism of ribavirin is based on the lethal mutagenesis/error catastrophe, that is, the ribavirin is not merely an antiviral reagent but also an effective mutagen.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.1
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• pp.209-213
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• 2007

In the recent, increased concern has been focused on the pharmacology and clinical utility of herbal extracts and derivatives as a drug or adjunct to chemotherapy and immunotherapy. Salicis Radicis Cortex, A decoction has been mainly used for improvement of ozena and a diuretic effect in oriental medicine, but there was no study on the molecular mechanism of Salicis Radicis Cortex as an immunomodulator. Here we investigated the role of the aqueous extract of Salicis Radicis Cortex in the expression of inflammatory mediators, surface molecule, and related receptors in vitro and in vivo. In murine macrophage RAW 264.7 cells and peritoneal macrophages of C57BL/6N mice, water extract of Salicis Radicis Cortex increased the production of secretary TNF-alpha and Nitric oxide, and the expression level of CD14, LPS co-receptor and CD86, co-stimulatory molecule compared to negative natural extract ex vivo. Moreover, i.p. injection of water extract of Salicis Radicis Cortex significantly increased the secretion level of IFN-gamma and TNF-alpha, IL-2, IL-4 and IL-5 in serum of mice in vivo. Taken together, these results suggest that Salicis Radicis Cortex may regulate the immune response by secreting Th1 and Th2 types of cytokines in vivo and the possibility of its as natural immunostimulator.

• Parasites, Hosts and Diseases
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• v.35 no.4
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• pp.245-250
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• 1997

The responses of gastric mucosal mast cells (GMMCS) to infection with coccid- ian protozoa, Clptosporinium muris, in mice were examined during primary and challenge infections. Each of three-week-old ICR SPF mice was orally inoculated with a single dose of 2 × 106 oocysts of C. muffs (strain MCR). After oocyst shedding ceased, the mice were orally challenged with a single dose of 2×106 oocysts of the same species. GMMCS reached a peak on days 20-30 postinoculation (Pl) in number, and decreased thereafter. An increase on days 20-30 post-challenge-infection (PCI) was also observed. The mice showed, on the whole, normal profiles of oocyst shedding in droppings. The number of the cells of uninfected control mice remained constant. .Tudging from the above results, it is suggested that mastocytosis correlate with expulsion of C. mans in primary infection and the defense mechanism of challenge infection.