• BMB Reports
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• v.48 no.12
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• pp.643-644
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• 2015

In eukaryotes, small RNAs play important roles in both gene regulation and resistance to viral infection. Argonaute proteins have been identified as a key component of the effector complexes of various RNA-silencing pathways, but the mechanistic roles of Argonaute proteins in these pathways are not clearly understood. To address this question, we performed single-molecule fluorescence experiments using an RNA-induced silencing complex (core-RISC) composed of a small RNA and human Argonaute 2. We found that target binding of core-RISC starts at the seed region of the guide RNA. After target binding, four distinct reactions followed: target cleavage, transient binding, stable binding, and Argonaute unloading. Target cleavage required extensive sequence complementarity and accelerated core-RISC dissociation for recycling. In contrast, the stable binding of core-RISC to target RNAs required seed-match only, suggesting a potential explanation for the seed-match rule of microRNA (miRNA) target selection.

• Fisheries and Aquatic Sciences
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• v.14 no.2
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• pp.148-160
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• 2011

Thirty-one gross abnormalities that have been observed in tilapia are described: 10 fin, five eye, five jaw, four body shape, three head, two yolk sac, one operculum, and conjoined twins. Twenty-one have been described in published papers; the others were obtained from a survey. Breeding experiments revealed that three were heritable, while six were not heritable. Five could be caused by a bacterial infection, and one could be produced by a fungus. Four deformities were in offspring of males that had been injected with methyl methane sulphonate. Three were produced when sperm was treated with methyl methane sulphonate. Six were observed during sex reversal studies, and one was found following heat shock of fertilized eggs. Three were observed in polluted river water. The cause of other deformities is not known.

• Korean Journal Plant Pathology
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• v.13 no.1
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• pp.18-21
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• 1997

Bipolaris panici-miliacei, Cercospora fusimaculans, Fusarium moniliforme and Rhizoctonia solani were pathogenic fungi detected from 5 seed samples of common millet (Panicum miliaceum). Morphological characters of B. panici-miliacei were as follows. Conidiophores were dark olivaceous brown, simple, cylindrical, geniculate, and septate. Conidia were fusoid, dark olivaceous brown, tapering gradually toward the ends, straight to slightly curved, 3~13 distoseptate, and 29.4~155.4$\times$10~26 ${\mu}{\textrm}{m}$ in size with dark hilum included within the contour of the basal cell. Seed infection with B. panici-miliacei caused seed rotting, coleoptile spot, and seedling blight of common millet plants. According to the inoculation experiments, B. panici-miliacei showed strong virulence on the young seedlings of common millet, but very weak virulence on the young seedlings of rice (Oryza sativa) and foxtail millet (Setaria italica).

• Proceedings of the Korean Society of Veterinary Pathology Conference
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• 2003.10a
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• pp.6-6
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• 2003

Listeria monocytogenes is a facultative bacterium that cause severe clinical disease including meningoencephalitis, septicaemia, and abortion in pregnant women, newborn infants, the debilitated elderly or immunocompromised people. In preliminary experiments on murine listeriosis we noticed suppurative gastritis in mice infected with L. monocytogenes by the intragastric route. The aims of the present study were ⅰ) to describe the histopathology of the experimentally listeria-induced gastroenteritis ⅱ) to investigate the influence of bacterial strain and laboratory mouse strain on infectivity and on the severity of the infection; [3] to examine possible effects of preliminary intragastric administration of sodium bicarbonate. (omitted)

• Journal of the Korean Magnetic Resonance Society
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• v.19 no.3
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• pp.143-148
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• 2015

In some pathogenic bacteria, there are RNA thermometers, which regulate the production of virulence associated factors or heat shock proteins depending on temperature changes. Like a riboswitches, RNA thermometers are located in the 5'-untranslated region and involved translational gene regulatory mechanism. RNA thermometers block the ribosome-binding site and start codon area under the $37^{\circ}C$ within their secondary structure. After bacterial infection, increased the temperature in the host causes conformations changes of RNA, and the ribosome-binding site is exposed for translational initiation. Because structural differences between open and closed forms of RNA thermometers are mainly mediated by base pairing changes, NMR spectroscopy is a very useful method to study these thermodynamically changing RNA structure. In this review, we briefly provide a fundamental function of RNA thermometers, and also suggest a proper NMR experiments for studying RNA thermometers.

• Natural Product Sciences
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• v.9 no.2
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• pp.60-63
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• 2003

Effect of grape seed extract (GSE) against Candida albicans was examined under in-vitro and in-vivo conditions. The GSE was extracted in ethanol. In-vitro results from an agar diffusion susceptibility assay showed the GSE inhibited C. albicans growth. This anticandidal effect was at dose-dependency. In experiments with animals, mice that received the GSE (0.5 mg per mice), intravenously (i.v.), before i.v.-infection wish viable C. albicans yeast cells survived longer than diluent (buffer)-received control mice. In contrast, when GSE was given to mice after the mice were infected with the yeast cells, these mice showed a similar survival rate as compared to control mice that received no treatment with the GSE. Taken together, these data indicate that GSE has prophylactic effect but not therapeutic effect against disseminated candidiasis.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.3B
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• pp.551-557
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• 2010

Fast spreading Internet worms will be sure to become one of the new major threats of convergence networks as well as the Internet. In order to defend and respond them, it is necessary to study how Internet worms propagate and what factors affect worm spreading. In this paper, we try to describe the correct spread of worms on convergence network environments. Therefore we propose a spreading model and analyze the spreading effects by various experiments.

• Proceedings of the PSK Conference
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• 2005.11a
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• pp.231-232
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• 2005

Bacteria of Shigella spp. are responsible for shigellosis in humans, a disease characterized by destruction of the colonic epithelium that is induced by the inflammatory response elicited by invasive bacteria. They use a type III secretion system injecting effector proteins into host cells to induce their entry into epithelial cells and triggers apoptosis in macrophages. We present evidence that the effector OspG is a protein kinase that binds various ubiquitinylated ubiquitin-conjugating enzymes (E2s) and blocks degradation of phospho-$I{\kappa}B{\alpha}$ induced upon entry of bacteria into epithelial cells. Transfection experiments confirmed that OspG interferes with the $NF-{\kappa}B$ activation patway by preventing phospho-$I{\kappa}B{\alpha}$ degradation, suggesting that OspG inactivates a component of the $SCF^{{\beta}-TrCP}$ ubiquitin ligase complex (E3) involved in phospho-$I{\kappa}B{\alpha}$ ubiquitination. Upon infection of ileal loops in rabbits, the ospG mutant induced a stronger inflammatory response compared with the wild-type strain, indicating that OspG down-regulates the host innate response induced by invasive bacteria.

• Korean Journal of Veterinary Research
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• v.37 no.4
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• pp.755-763
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• 1997

Recently new technologies for the establishment of high health herds are becoming efficient tools in the control of PRRS virus and secondary infections. Medicated early weaning(MEW) and nursery depopulation(ND) have shown to be one of the most successful procedures in the eradication and control of pathogens. Indirect evidence of the role of PRRSV in precipitating secondary infection comes from successful improvement in growth and in decreasing mortality on farms that have eliminated PRRSV through ND. Hence the present experiments were conducted in an effort to compare ND with MEW procedures as a means of eliminating PRRSV controlling secondary pathogens and improving performance of pigs in endemically infected swine herds. Following MEW and ND procedures practiced in the farms, some benefits obtained were as follows: 1. A decrease in PRRSV circulation in the nursery, but no entire elimination. 2. Decrease in the frequency of secondary bacteria and in the use of antibiotics. 3. Mycoplasma hyopneumoniae infection was prevented during the nursery stage. 4. ND protocol had a lower cost and management changes than MEW techniques. 5. Nursery performance was improved after the depopulation, cleaning and disinfection procedures, even though PRRSV still being cycled in the old nursery rooms. These studies revealed that the MEW and ND protocols are not always successful for PRRS virus elimination but it's great effect on control of secondary pathogens and improvement of performance make MEW and ND an efficient tools for the establishment of healthier and more efficient herds.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.1
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• pp.63-72
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• 2012

In livestock industry, damage caused by the epidemic diseases such as Foot-and-Mouth Disease (FMD), Highly-Pathogenic-Avian-Influenza (HPAI) and Porcine-Reproductive-and-Respiratory-Syndrome (PRRS) was very serious. The financial loss incurred from FMD alone which occurred on Nov. 2011 in Korea was estimated at 3 billion won, 23 % of annual livestock industry production. The livestock industry in Korea has greater risk of disease infection because of high density production, etc. Investigating the spread of livestock diseases should consider both direct and indirect contact as well as other various factors including airborne. Airborne infection of livestock disease was first hypothesised in the early 1900s, however, field experimental studies are still limited. Furthermore, no protocol is available in detecting airborne viruses in the field. In this study, effective virus samplers were investigated by comparative analysis of the type of samplers used detect to airborne virus. Laboratory experiments were conducted to compare virus samplers such as Bio-sampler, Dust-sampler, Compact-Cascade-Impactor (CCI) and Microflow in detecting PRRSV. Samples were analyzed by Reverse-Transcription PCR to assess the efficiency of the instrument in detecting the airborne virus. First, samples were classified into five levels according to light intensity of gel images and then the classified results were normalized. In every case, Bio-sampler and Dust-sampler were comparable with each other and have shown to be more effective than CCI and Microflow samplers.