• Proceedings of the PSK Conference
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• 2002.10a
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• pp.151-152
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• 2002

Bacterial infection is a very complex process in which both pathogenic microorganisms and host cells play crucial roles, and it is the outcome of interactions between the two participants. To elucidate the bacterial pathogenesis mechanisms, therefore, it is essential to understand the cellular and systemic responses of the host as well as the virulence factors of the pathogen. Infection of a host by pathogenic bacteria causes drastic changes in the physiology of host cells, leading to activation of a program of various gene expression. (omitted)

• Journal of Microbiology and Biotechnology
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• v.32 no.7
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• pp.844-854
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• 2022

Helicobacter pylori, a group 1 carcinogen, colonizes the stomach and affects the development of stomach diseases. Progranulin (PGRN) is an autocrine growth factor that regulates multiple cellular processes and plays a tumorigenic role in many tissues. Nevertheless, the mechanism of action of PGRN in gastric cancer caused by H. pylori infection remains unclear. Here, we investigated the role of PGRN in cell cycle progression and the cell proliferation induced by H. pylori infection. We found that the increased PGRN was positively associated with CDK4 expression in gastric cancer tissue. PGRN was upregulated by H. pylori infection, thereby promoting cell proliferation, and that enhanced level of proliferation was reduced by PGRN inhibitor. CDK4, a target gene of PGRN, is a cyclin-dependent kinase that binds to cyclin D to promote cell cycle progression, which was upregulated by H. pylori infection. We also showed that knockdown of CDK4 reduced the higher cell cycle progression caused by upregulated PGRN. Moreover, when the PI3K/Akt signaling pathway (which is promoted by PGRN) was blocked, the upregulation of CDK4 mediated by PGRN was reduced. These results reveal the potential mechanism by which PGRN plays a major role through CDK4 in the pathological mechanism of H. pylori infection.

• Korean Journal of Veterinary Service
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• v.45 no.2
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• pp.87-99
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• 2022

A novel porcine circovirus 4 (PCV4) was recently emerged in Chinese and Korean pig herds, which provided epidemiological situation where three pathogenic PCVs, PCV2, PCV3, and newly emerged PCV4, could co-infect pig herds in these countries. In this study, a new triplex quantitative real-time polymerase chain reaction (tqPCR) method was developed for the rapid and differential detection of these viruses. The assay specifically amplified each viral capsid gene, whereas no other porcine pathogenic genes were detected. The detection limit of the assay was below 10 copies/µL and the assay showed high repeatability and reproducibility. In the clinical evaluation using 1476 clinical samples from 198 Korean pig farms, the detection rates of PCV2, PCV3 and PCV4 by the tqPCR assay were 13.8%, 25.4%, and 3.8%, respectively, which were 100% agreement with those of previously reported monoplex qPCR assays for PCV2, PCV3, and PCV4, with a κ value (95% CI) of 1 (1.00~1.00). The prevalence of PCV2, PCV3, and PCV4 at the farm levels were 46.5%, 63.6%, and 19.7%, respectively. The co-infection analysis for tested pig farms showed that single infection rates for PCV2, PCV3, and PCV4 were 28.8%, 44.4%, and 9.6%, respectively, the dual infection rates of PCV2 and PCV3, PCV2 and PCV4, and PCV3 and PCV4 were 12.6%, 3.5%, and 5.1%, respectively, and the triple infection rate for PCV2, PCV3, and PCV4 was 1.5%. These results demonstrate that three pathogenic PCVs are widely spread, and their co-infections are common in Korean pig herds, and the newly developed tqPCR assay will be useful for etiological and epidemiological studies of these pathogenic PCVs.

• The Plant Pathology Journal
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• v.40 no.3
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• pp.235-250
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• 2024

During the infection process, plant pathogenic fungi encounter plant-derived oxidative stress, and an appropriate response to this stress is crucial to their survival and establishment of the disease. Plant pathogenic fungi have evolved several mechanisms to eliminate oxidants from the external environment and maintain cellular redox homeostasis. When oxidative stress is perceived, various signaling transduction pathways are triggered and activate the downstream genes responsible for the oxidative stress response. Despite extensive research on antioxidant systems and their regulatory mechanisms in plant pathogenic fungi, the specific functions of individual antioxidants and their impacts on pathogenicity have not recently been systematically summarized. Therefore, our objective is to consolidate previous research on the antioxidant systems of plant pathogenic fungi. In this review, we explore the plant immune responses during fungal infection, with a focus on the generation and function of reactive oxygen species. Furthermore, we delve into the three antioxidant systems, summarizing their functions and regulatory mechanisms involved in oxidative stress response. This comprehensive review provides an integrated overview of the antioxidant mechanisms within plant pathogenic fungi, revealing how the oxidative stress response contributes to their pathogenicity.

• The Korean Journal of Emergency Medical Services
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• v.20 no.3
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• pp.49-56
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• 2016

Purpose: The purpose of this study was to investigate the effect of a pathogenic bacteria filtration instrument for infection prevention during mouth-to-mouth ventilation. Methods: Two kinds of face shields were used for the study. One rescuer blew the filter through a bag valve mask and the filter was then cultured for bacteria. The mask was tested both on the front and back side. Results: Two kinds of face shields including the KF shield and CM shield were tested. The KF shield has received national certification and it prevented transmission of bacterial infection but the CM shield showed the opposite result and did not prevent bacterial transmission. Pathogenic bacteria were found on the back of the CM shield. Conclusion: A certified face shield is very important to prevent bacterial transmission. Face shields should be demonstrated and used by paramedic students.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.5
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• pp.1233-1237
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• 2005

Catechin products in green tea extract was prepared to investigate antibacterial activity on the pathogenic bacteria. Survival of pathogenic bacteria (MASA - methicillin resistant Staphylocouus aureus, E.coli O157 and S. typhimurium Sal-13) in tryptic soy agar(TSA) containing Catechin products powder incubated at various concentration was evaluated. TSA containing $0{\sim}2%(w/v)$ of Catechin products was inoculated approximately $10^4\;CFU/ml$ of pathogenic bacteria and incubated at $37^{\circ}C$ for 24 hours. The plate counting technique and clear zoon test were used to test survival effect of the Catechin products. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) was derived from the survival curves of pathogenic bacteria. S. typhimurium Sal-13 was the most sensitive strain to Catechin products. This result suggested that Catechin products can be used as an effective natural antibacterial agent.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.4
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• pp.622-627
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• 2012

The processes to determine the composition, dynamics, and activity of infection mechanisms by the rhizosphere microflora have attracted the interest of scientists from multiple disciplines although considerable progress of the infection pathways and plant-pathogen interactions by soil borne fungal pathogens have been made. Soilborne pathogens are confined within a three-dimensional matrix of mineral soil particles, pores, organic matter in various stages of decomposition and a biological component. Among the physical and chemical properties of soils soil texture and matric water potential may be the two most important factors that determine spread exudates by soil borne fungal pathogens, based on the size of the soil pores. Pathogenic invasion of plant roots involves complex molecular mechanisms which occur in the diffuse interface between the root and the soil created by root exudates. The initial infection by soilborne pathogens can be caused by enzymes which breakdown cell wall layers to penetrate the plant cell wall for the fungus. However, the fate and mobility of the exudates are less well understood. Therefore, it needs to develop methods to control disease caused by enzymes produced by the soilborne pathogens by verifying many other possible pathways and mechanisms of infection processes occurring in soils.

• Journal of Microbiology and Biotechnology
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• v.25 no.4
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• pp.479-491
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• 2015

Lactobacillus species have been shown to enhance intestinal epithelial barrier function, modulate host immune responses, and suppress the growth of pathogenic bacteria, yeasts, molds, and viruses. Thus, lactobacilli have been used as probiotics for treating various diseases, including intestinal disorders, and as biological preservatives in the food and agricultural industries. However, the molecular mechanisms used by lactobacilli to suppress pathogenic bacterial infections have been poorly characterized. We previously isolated Lactobacillus plantarum JSA22 from buckwheat sokseongjang, a traditional Korean fermented soybean food, which possessed high enzymatic, fibrinolytic, and broad-spectrum antimicrobial activity against foodborne pathogens. In this study, we investigated the effects of L. plantarum JSA22 on the growth of S. Typhimurium and S. Typhimurium-induced cytotoxicity by stimulating the host immune response in intestinal epithelial cells. The results showed that coincubation of S. Typhimurium and L. plantarum JSA22 with intestinal epithelial cells suppressed S. Typhimurium infection, S. Typhimurium-induced NF-κB activation, and IL-8 production, and lowered the phosphorylation of both Akt and p38. These data indicated that L. plantarum JSA22 has probiotic properties, and can inhibit S. Typhimurium infection of intestinal epithelial cells. Our findings can be used to develop therapeutic and prophylactic agents against pathogenic bacteria.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.111.1-111.1
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• 2003

Bacterial infection is a very complex process in which both pathogens and host cells play crucial roles, and the host cells undergo drastic changes in their physiology, releasing various proteins in response to the pathogenic infection. Human airway epithelial surface serves as a first line of defense against microorganisms and the external environment. It is well known that bronchial epithelial cells secrete various chemokines and cytokines such as IL-6 and IL-8 to cope with various respiratory pathogens. (omitted)

• Korean Journal Plant Pathology
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• v.10 no.3
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• pp.197-210
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• 1994

This experiment was carried out to study the cause of degeneration and rot of cultivated mushroom. Among 597 bacterial isolates derived from the rots of Button mushroom (Agaricus bisporus), Oyster mushroom (Pleurotus ostreatus) and Oak mushroom (Lentinus edodes) collected from markets of 5 cities (Seoul, Suwon, Taegu, Pohang and Pusan) in Korea (1991~1993), 111 bacterial isolates (18.5%) were proved as pathogenic bacteria. These pathogenic bacteria causing bacterial rots of cultivated mushrooms were identified as Pseudomonas tolasii, P. agarici, and Eriwinia sp., and the main causal bacteria were P. tolaasii. P. fluorescens and Klebsiella plenticola were confirmed as saprophytic non-pathogenic bacteria. One hundred fifty nine isolates (Group No. 39) of the 486 saprophytic bacterial isolates were classified as P. fluorescens, and this species was most often found rot area of cultivated mushrooms. P. tolaasii, the causal organism of bacterial blotch, was classified into two groups; One group can be differentiated from the other by the formation of white precipitation band by white line reacting organisms of Pseudomonas Agar F media. P. tolaasii attacked the cultivated mushrooms relatively well at lower incubation temperature such as 5$^{\circ}C$, but P. agarici rarely attack at below 1$0^{\circ}C$. The temperature for the infection commercial cultivated mushrooms by P. agarici was higher than that of P. tolaasii. Optimum temperature for the infection of mushrooms by P. tolaasii and P. agarici were 2$0^{\circ}C$ and $25^{\circ}C$, respectively.