• Journal of the Korean Chemical Society
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• v.59 no.1
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• pp.22-30
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• 2015

The effect of diphtheria toxin on cell membrane lipids was studied by examining the phospholipase D (PLD) activity and free fatty acids (FFA) release in HepG2 cells. The diphtheria toxin effects on lipid alteration show apparently maximal at pH 5.1, stimulating PLD activity nearly 3.5 fold and enhancing FFA release approximately 5 fold over the control. These results indicate that the membrane is perturbed and its lipid component is rearranged during the diphtheria toxin translocation. Digitonin, a random membrane perturbing detergent, exhibit about four-fold higher perturbation effect over the diphtheria toxin at neutral pH. This observation suggests that the membrane perturbation induced by diphtheria toxin appears to be rather selective. To investigate the cause of the membrane perturbation, Cibacron blue, an inhibitor of membrane pore formation, and hemagglutinin, an influenza virus with fusion peptide, were tested for their effects on diphtheria toxin action. Cibacron blue decreased the diphtheria toxin effect by almost 50%, but the lipid alteration induced by hemagglutinin was similar to the diphtheria toxin effect. These observations imply that the membrane perturbation induced by diphtheria toxin may be caused by a combination of pore formation and insertion of hydrophobic peptide of toxin to the membrane as well. Additionally, we found that the diphtheria toxin increased the HepG2 cells permeability but the cells viability was maintained at high level at the same time. DNA fragmentation which is related to apoptosis was not induced by the toxin. Under these conditions, we could demonstrate that the lipid alteration of HepG2 cells was brought about by diphtheria toxin at acidic pH.

• Korean Journal of Poultry Science
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• v.46 no.4
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• pp.235-247
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• 2019

Serological monitoring has been conducted worldwide for early diagnosis of disease and monitoring of immune status in poultry. This study was conducted to evaluate the immune status of layers with sera submitted to the Avian Disease Laboratory, Chungbuk National University from 2015 to 2017. The test results were analyzed by the time submitted and by the age of the chicks. Low pathogenic avian influenza (LPAI) showed a low positive rate of antibody compared with those of Newcastle disease, indicating that domestic vaccination against LPAI was not sufficient. The antibody profile of infectious bronchitis (IB) depicted high level of titer and a low tendency of CV as compared to the uninfected control flocks, which indicated that most layer farms have been exposed to the field IB virus. In case of avian metapneumovirus infection (aMPV) and Mycoplasma synoviae (MS), since the introduction of the vaccine in 2011 and 2017, respectively, the positive rate and the titer level were higher than those in pevious times. No significant difference in the changes of seasonal result was observed, indicating proper vaccination and improvement in biosecurity and management.

• Plant Breeding and Biotechnology
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• v.6 no.4
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• pp.404-412
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• 2018

The influenza neuraminidase (NA, E.C. 3.2.1.18), an antiviral, has been the target of high pharmaceutical companies due to its essential role in viral replication cycle. Perilla frutescens (P. frutescens) is used in traditional Chinese medicine for various diseases, such as cold due to wind-cold, headache and cough. In this context, four major polyphenolic compounds including rosmarinic acid-3-O-glucoside (1), rosmarinic acid (2), luteolin (3), and apigenin (4) isolated from P. frutescens were evaluated for their inhibitory effect on recombinant virus H1N1 neuraminidase (rvH1N1 NA). Among the test compounds, rosmarinic acid and luteolin inhibited the rvH1N1 NA with an $IC_{50}$ of 46.7 and $8.4{\mu}M$, respectively. The inhibition kinetics analyzed by the Dixon plots indicated that rosmarinic acid and luteolin were noncompetitive inhibitors and that the inhibition constant, $K_I$, was established as 43.9 and $14.3{\mu}M$, respectively. In addition, 578 genetically diverse accessions and 39 cultivars of P. frutescens were analyzed using HPLC to characterize the diversity of polyphenolic composition and concentration. The individual and total compositions exhibited significant difference (P < 0.05), especially rosmarinic acid which was detected as the predominant metabolite in all accessions (58.8%) and cultivars (62.8%). Yeupsil and Sangback cultivars exhibited the highest rosmarinic acid ($3,393.5{\mu}g/g$) and luteolin ($383.3{\mu}g/g$) content respectively. YCPL177-2 with the high concentration ($889.8{\mu}g/g$) of luteolin may be used as a genetic resource for breeding elite cultivars.

• Korean Journal of Poultry Science
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• v.48 no.4
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• pp.169-176
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• 2021

An experiment was conducted to investigate the effects of varying levels of hydrolyzed yeast on egg production and egg quality in aged laying randomly allotted to three dietary treatments such that egg production was similar in each treatment (6 replicates of 10 birds each). The layers were fed diets containing 0, 0.1, or 0.2% hydrolyzed yeast for eight weeks. No significant difference was observed in egg production during the first half of the experiment. Egg production and daily egg mass in groups fed diets containing hydrolyzed yeast were significantly higher (P<0.05) than those of the control groups during the second half of the experiment. Egg weight was not affected by the dietary treatment. Eggshell strength and thickness in groups fed diets containing hydrolyzed yeast were significantly higher than those of the control groups during the overall experimental period (P<0.05). Although no significant differences were observed in the Haugh units, yolk color in the group fed diets containing 0.1% hydrolyzed yeast was significantly higher than that in the control group (P<0.05). The mammillary layer thickness increased in a linear manner and significantly following treatment with dietary hydrolyzed yeast (P<0.05). Antibody titer against avian influenza virus in the group fed diets containing 0.2% hydrolyzed yeast was significantly higher (P<0.05) than that in the control group. In conclusion, dietary hydrolyzed yeast improved egg production and eggshell quality of laying hens in the late stages of production.

• Animal Bioscience
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• v.36 no.6
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• pp.851-860
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• 2023

Objective: This study aims to evaluate the target genes of gga-miR-20a-5p and the regulated immune responses in the chicken macrophage cell line, HD11, by the exosome-mediated delivery of miR-20a-5p. Methods: Exosomes were purified from the chicken macrophage cell line HD11. Then, mimic gga-miR-20p or negative control miRNA were internalized into HD11 exosomes. HD11 cells were transfected with gga-miR-20a-5p or negative control miRNA containing exosomes. After 44 h of transfection, cells were incubated with or without 5 ㎍/mL poly(I:C) for 4 h. Then, expression of target genes and cytokines was evaluated by quantitative realtime polymerase chain reaction. Results: Using a luciferase reporter assay, we identified that gga-miR-20a-5p directly targeted interferon gamma receptor 2 (IFNGR2), mitogen-activated protein kinase 1 (MAPK1), mitogen-activated protein kinase kinase kinase 5 (MAP3K5), and mitogen-activated protein kinase kinase kinase 14 (MAP3K14). Moreover, the exosome-mediated delivery of gga-miR-20a-5p successfully repressed the expression of IFNGR2, MAPK1, MAP3K5, and MAP3K14 in HD11 cells. The expressions of interferon-stimulated genes (MX dynamin like GTPase 1 [MX1], eukaryotic translation initiation factor 2A [EIF2A], and oligoadenylate synthase-like [OASL]) and proinflammatory cytokines (interferon-gamma [IFNG], interleukin-1 beta [IL1B], and tumor necrosis factor-alpha [TNFA]) were also downregulated by exosomal miR-20a-5p. In addition, the proliferation of HD11 cells was increased by exosomal miR-20a-5p. Conclusion: The exosome-mediated delivery of gga-miR-20a-5p regulated immune responses by controlling the MAPK and apoptotic signaling pathways. Furthermore, we expected that exosomal miR-20a-5p could maintain immune homeostasis against highly pathogenic avian influenza virus H5N1 infection by regulating the expression of proinflammatory cytokines and cell death.

• Pediatric Infection and Vaccine
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• v.28 no.2
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• pp.101-109
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• 2021

Purpose: Common human coronaviruses (HCoVs) are relatively understudied due to the mild nature of HCoV infection. Given the lack of local epidemiology data on common HCoVs, we aimed to describe clinical and epidemiological characteristics of common HCoVs in children. Methods: Respiratory viral test results from 9,589 respiratory samples from Seoul National University Children's Hospital were analyzed from January 2015 to December 2019. Viral detection was done by the multiplex reverse transcription polymerase chain reaction. Demographics and clinical diagnosis were collected for previously healthy children tested positive for HCoVs. Results: Of the 9,589 samples tested, 1 or more respiratory viruses were detected from 5,017 (52.3%) samples and 463 (4.8%) samples were positive for HCoVs (OC43 2.8%, NL63 1.4%, 229E 0.7%). All 3 types co-circulated during winter months (November to February) with some variation by type. HCoV-OC43 was the most prevalent every winter season. HCoV-NL63 showed alternate peaks in late winter (January to March) and early winter (November to February). HCoV-229E had smaller peaks every other winter. Forty-one percent of HCoV-positive samples were co-detected with additional viruses; human rhinovirus 13.2%, respiratory syncytial virus 13.0%, influenza virus 4.3%. Common clinical diagnosis was upper respiratory tract infection (60.0%) followed by pneumonia (14.8%), croup (8.1%), and bronchiolitis (6.7%). Croup accounted for 17.0% of HCoV-NL63-positive children. Conclusions: This study described clinical and epidemiological characteristics of common HCoVs (OC43, NL63, 229E) in children. Continuing surveillance, perhaps by adding HKU1 in the diagnostic panel can further elucidate the spectrum of common HCoV infections in children.

• Tuberculosis and Respiratory Diseases
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• v.58 no.2
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• pp.167-173
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• 2005

Background : Airborne particles during Yellow Sand phenomena are known to be associated with the respiratory disease. The purpose of this study was to evaluate the concentration and metal component properties of Yellow Sand particles and compare with airborne microbial concentration and species in non Yellow Sand and Yellow Sand phenomena. Methods : Samplings were carried out in 2002 in Seosan, during non Yellow Sand and Yellow Sand phenomena. Samples were taken using the 8-stage Cascade impactor and metallic elements were analyzed by XRF. Those were culture on the media for bacterial and fungal culture and celline for virus. Results : The concentration of total suspended particulate matter were respectively $80.2{\mu}g/m^3$, $40.3{\mu}g/m^3$ in non Yellow Sand and Yellow Sand phenomena. The concentration of metallic elements such as Ca, Fe, Cu and Zn in Yellow Sand phenomena were higher than its in non Yellow Sand. Two bacteria, Bacillus species and Staphylococcus were grown in two periods. In both periods, several fungal spores(Mucor species, Cladosporum, Alternaria, Aspergillus, Penicillium, and Alternaria species) were identified. The differences of bacteria and fungus species not observed in Yellow Sand and non Yellow Sand. Any viruses were not isolated in between both periods. Conclusions : The concentration of total suspended particulate matter and some metallic elements in Yellow Sand phenomena were higher than its in non Yellow Sand. The difference of bacteria and fungus species was not observed in non Yellow Sand and Yellow Sand phenomena.

• Tuberculosis and Respiratory Diseases
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• v.85 no.1
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• pp.37-46
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• 2022

Background: Although respiratory tract infection is one of the most important factors triggering acute exacerbation of chronic obstructive pulmonary disease (AE-COPD), limited data are available to suggest an epidemiologic pattern of microbiology in South Korea. Methods: A multicenter observational study was conducted between January 2015 and December 2018 across 28 hospitals in South Korea. Adult patients with moderate-to-severe acute exacerbations of COPD were eligible to participate in the present study. The participants underwent all conventional tests to identify etiology of microbial pathogenesis. The primary outcome was the percentage of different microbiological pathogens causing AE-COPD. A comparative microbiological analysis of the patients with overlapping asthma-COPD (ACO) and pure COPD was performed. Results: We included 1,186 patients with AE-COPD. Patients with pure COPD constituted 87.9% and those with ACO accounted for 12.1%. Nearly half of the patients used an inhaled corticosteroid-containing regimen and one-fifth used systemic corticosteroids. Respiratory pathogens were found in 55.3% of all such patients. Bacteria and viruses were detected in 33% and 33.2%, respectively. Bacterial and viral coinfections were found in 10.9%. The most frequently detected bacteria were Pseudomonas aeruginosa (9.8%), and the most frequently detected virus was influenza A (10.4%). Multiple bacterial infections were more likely to appear in ACO than in pure COPD (8.3% vs. 3.6%, p=0.016). Conclusion: Distinct microbiological patterns were identified in patients with moderate-to-severe AE-COPD in South Korea. These findings may improve evidence-based management of patients with AE-COPD and represent the basis for further studies investigating infectious pathogens in patients with COPD.

• Journal of Internet Computing and Services
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• v.14 no.5
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• pp.69-76
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• 2013

The incidence of globally infectious and pathogenic diseases such as H1N1 (swine flu) and Avian Influenza (AI) has recently increased. An infectious disease is a pathogen-caused disease, which can be passed from the infected person to the susceptible host. Pathogens of infectious diseases, which are bacillus, spirochaeta, rickettsia, virus, fungus, and parasite, etc., cause various symptoms such as respiratory disease, gastrointestinal disease, liver disease, and acute febrile illness. They can be spread through various means such as food, water, insect, breathing and contact with other persons. Recently, most countries around the world use a mathematical model to predict and prepare for the spread of infectious diseases. In a modern society, however, infectious diseases are spread in a fast and complicated manner because of rapid development of transportation (both ground and underground). Therefore, we do not have enough time to predict the fast spreading and complicated infectious diseases. Therefore, new system, which can prevent the spread of infectious diseases by predicting its pathway, needs to be developed. In this study, to solve this kind of problem, an integrated monitoring system, which can track and predict the pathway of infectious diseases for its realtime monitoring and control, is developed. This system is implemented based on the conventional mathematical model called by 'Susceptible-Infectious-Recovered (SIR) Model.' The proposed model has characteristics that both inter- and intra-city modes of transportation to express interpersonal contact (i.e., migration flow) are considered. They include the means of transportation such as bus, train, car and airplane. Also, modified real data according to the geographical characteristics of Korea are employed to reflect realistic circumstances of possible disease spreading in Korea. We can predict where and when vaccination needs to be performed by parameters control in this model. The simulation includes several assumptions and scenarios. Using the data of Statistics Korea, five major cities, which are assumed to have the most population migration have been chosen; Seoul, Incheon (Incheon International Airport), Gangneung, Pyeongchang and Wonju. It was assumed that the cities were connected in one network, and infectious disease was spread through denoted transportation methods only. In terms of traffic volume, daily traffic volume was obtained from Korean Statistical Information Service (KOSIS). In addition, the population of each city was acquired from Statistics Korea. Moreover, data on H1N1 (swine flu) were provided by Korea Centers for Disease Control and Prevention, and air transport statistics were obtained from Aeronautical Information Portal System. As mentioned above, daily traffic volume, population statistics, H1N1 (swine flu) and air transport statistics data have been adjusted in consideration of the current conditions in Korea and several realistic assumptions and scenarios. Three scenarios (occurrence of H1N1 in Incheon International Airport, not-vaccinated in all cities and vaccinated in Seoul and Pyeongchang respectively) were simulated, and the number of days taken for the number of the infected to reach its peak and proportion of Infectious (I) were compared. According to the simulation, the number of days was the fastest in Seoul with 37 days and the slowest in Pyeongchang with 43 days when vaccination was not considered. In terms of the proportion of I, Seoul was the highest while Pyeongchang was the lowest. When they were vaccinated in Seoul, the number of days taken for the number of the infected to reach at its peak was the fastest in Seoul with 37 days and the slowest in Pyeongchang with 43 days. In terms of the proportion of I, Gangneung was the highest while Pyeongchang was the lowest. When they were vaccinated in Pyeongchang, the number of days was the fastest in Seoul with 37 days and the slowest in Pyeongchang with 43 days. In terms of the proportion of I, Gangneung was the highest while Pyeongchang was the lowest. Based on the results above, it has been confirmed that H1N1, upon the first occurrence, is proportionally spread by the traffic volume in each city. Because the infection pathway is different by the traffic volume in each city, therefore, it is possible to come up with a preventive measurement against infectious disease by tracking and predicting its pathway through the analysis of traffic volume.