• 한국동물학회:학술대회논문집
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• 한국동물학회 2000년도 한국생물과학협회 학술발표대회
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• pp.248.1-248
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• 2000

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• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제17권3호
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• pp.140-146
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• 2014

Purpose: The etiology of acute gastroenteritis (AGE) has changed since the introduction of the rotavirus vaccination. The aim of this study was to clarify which common pathogens, both bacterial and viral, are currently causing AGE in infants. Methods: Infants with acute diarrhea were enrolled. We tested for 10 bacterial pathogens and five viral pathogens in stool specimens collected from infants with AGE. The clinical symptoms such as vomiting, mucoid or bloody diarrhea, dehydration, irritability, and poor oral intake were recorded, and laboratory data such as white blood cell count and C-reactive protein were collected. The clinical and laboratory data for the cases with bacterial pathogens and the cases with viral pathogens were compared. Results: Of 41 total infants, 21 (51.2%) were positive for at least one pathogen. Seventeen cases (41.5%) were positive for bacterial pathogens and seven cases (17.1%) were positive for viral pathogens. Staphylococcus aureus (13 cases, 31.7%) and Clostridium perfringens (four cases, 9.8%) were common bacterial pathogens. Norovirus (five cases, 12.2%) was the most common viral pathogen. Fever and respiratory symptoms were common in the isolated viral infection group (p=0.023 and 0.044, respectively), whereas other clinical and laboratory data were indistinguishable between the groups. Conclusion: In our study, S. aureus (41.5%) and norovirus (12.2%) were the most common bacterial and viral pathogens, respectively, among infants with AGE.

• The Plant Pathology Journal
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• 제30권4호
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• pp.331-342
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• 2014

Given the lack of a resistant genetic pool in host plants, the introduction of exotic invasive pathogens can result in epidemics that affect a specific ecosystem and economy. Plant quarantine, which is designed to protect endemic plant resources, is a highly invaluable safeguard that should keep biosecurity with increasing international trade and global transportation. A total of 34 species of plant pathogens including Phytophthora infestans were documented as introduced from other countries into Korea from 1900 to 2010. The genus Phytophthora, classified in oomycetes, includes more than 120 species that are mostly recognized worldwide as highly invasive plant pathogens. After 2000, over 50 new species of Phytophthora were identified internationally as plant pathogens occurring in crops and forest trees. In Korea, Phytophthora is also one of the most serious plant pathogens. To date, 22 species (about one-fifth of known species) of the genus have been identified and reported as plant pathogens in the country. The likelihood of new exotic Phytophthora species being introduced into Korea continues to increase, thus necessitating intensive plant quarantine inspections. As new potential threats to plant health in Korea, six Phytophthora species, namely, P. alni, P. inundata, P. kernoviae, P. pinifolia, P. quercina, and P. ramorum, are discussed in this review with focus on history, disease, biology, management, and plant quarantine issues.

• Mycobiology
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• 제31권4호
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• pp.251-254
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• 2003

To select active bacterial strains to control plant diseases, 57 bacterial strains were isolated from the rhizosphere of the plants growing in various areas such as coast, middle and top of Halla Mountain in Jeju Island. Anti-fungal effect of isolated bactrial strains was tested in vitro by incubating in potato dextrose agar with isolates of four fungal plant pathogens Rhizoctonia solani, Fusarium oxysporum, Colletotrichum gloeosporioides and C. orbiculare, respectively. Thirty-four bacterial strains inhibited the hyphal growth of the plant pathogens, from which 17 strains inhibited one of the tested fungi, 10 strains two fungi, six strains three and a strain TRL2-3 inhibited all of the tested fungi. Some bacterial strains could inhibit weakly the hyphal growth of the plant pathogens, whereas some did very strongly with apparent inhibition zone between the plant pathogens and bacterial strains indicating the unfavorable condition for hyphal growth. Although there was no apparent inhibition zone, some bacterial strains showed a strong suppression of hyphal growth of plant pathogens. Especially, the inhibition by TRL2-3 was remarkably strong in all cases of the tested plant pathogens in this study that could be a possible candidate for biological control of various plant diseases.

• The Plant Pathology Journal
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• 제38권1호
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• pp.25-32
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• 2022

Plant pathogens pose major threats on agriculture and horticulture, causing significant economic loss worldwide. Due to the continuous and excessive use of synthetic pesticides, emergence of pesticide resistant pathogens has become more frequent. Thus, there is a growing needs for environmentally-friendly and selective antimicrobial agents with a novel mode of action, which may be used in combination with conventional pesticides to delay development of pesticide resistance. In this study, we evaluated the potentials of lichen substances as novel biopesticides against eight bacterial and twelve fungal plant pathogens that have historically caused significant phytopathological problems in South Korea. Eight lichen substances of diverse chemical origins were extracted from axenic culture or dried specimen, and further purified for comparative analysis of their antimicrobial properties. Usnic acid and vulpinic acid exhibited strong antibacterial activities against Clavibacter michiganensis subsp. michiganensis. In addition, usnic acid and vulpinic acid were highly effective in the growth inhibition of fungal pathogens, such as Diaporthe eres, D. actinidiae, and Sclerotinia sclerotiorum. Intriguingly, the growth of Rhizoctonia solani was specifically inhibited by lecanoric acid, indicating that lichen substances exhibit some degrees of selectivity to plant pathogens. These results suggested that lichen substance can be used as a selective biopesticide for controlling plant disease of agricultural and horticultural significance, minimizing possible emergence of pesticide resistant pathogens in fields.

• The Plant Pathology Journal
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• 제39권5호
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• pp.449-465
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• 2023

Plants are challenged by various pathogens throughout their lives, such as bacteria, viruses, fungi, and insects; consequently, they have evolved several defense mechanisms. In addition, plants have developed localized and systematic immune responses due to biotic and abiotic stress exposure. Animals are known to activate DNA damage responses (DDRs) and DNA damage sensor immune signals in response to stress, and the process is well studied in animal systems. However, the links between stress perception and immune response through DDRs remain largely unknown in plants. To determine whether DDRs induce plant resistance to pathogens, Arabidopsis plants were treated with bleomycin, a DNA damage-inducing agent, and the replication levels of viral pathogens and growth of bacterial pathogens were determined. We observed that DDR-mediated resistance was specifically activated against viral pathogens, including turnip crinkle virus (TCV). DDR increased the expression level of pathogenesis-related (PR) genes and the total salicylic acid (SA) content and promoted mitogen-activated protein kinase signaling cascades, including the WRKY signaling pathway in Arabidopsis. Transcriptome analysis further revealed that defense-and SA-related genes were upregulated by DDR. The atm-2atr-2 double mutants were susceptible to TCV, indicating that the main DDR signaling pathway sensors play an important role in plant immune responses. In conclusion, DDRs activated basal immune responses to viral pathogens.

• Fisheries and Aquatic Sciences
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• 제21권7호
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• pp.18.1-18.6
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• 2018

Background: Cutaneous bacterial pathogens including Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Propionibacterium acnes are often involved in acne vulgaris. The currently available therapeutic option for these skin pathogens is an antibiotic treatment, resulting in the emergence of antibiotic-resistant bacteria. The objective of this study was to discover an alternative antibacterial agent with lower side effect from marine algae. Results: The ethanolic extract of edible brown algae Ishige okamurae exhibits potent antibacterial activity against cutaneous bacterial pathogens. Among the ethanol soluble fractions, the n-hexane (Hexane)-soluble fraction exhibited the strongest antibacterial activity against the pathogens with MIC values ranging 64 to $512{\mu}g/mL$ and with minimum bactericidal concentration values ranging 256 to $2048{\mu}g/mL$. Furthermore, the combination with Hexane fraction and antibiotics (ceftazidime, ciprofloxacin, and meropenem) exhibited synergistic effect. Conclusion: This study revealed that the I. okamurae extract exhibited a synergistic antibacterial effect against acnerelated cutaneous bacterial pathogens acquired antibiotic resistant. Thus, the results of the present study suggested that the edible seaweed extract will be a promising antibacterial therapeutic agent against antibiotic-human skin pathogens and its infections.

• The Plant Pathology Journal
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• 제30권4호
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• pp.397-406
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• 2014

Maize is a socioeconomically important crop in many countries. Recently, a high incidence of stalk rot disease has been reported in several maize fields in Gangwon province. In this report, we show that maize stalk rot is associated with the fungal pathogens Fusarium subglutinans and F. temperatum. Since no fungicides are available to control these pathogens on maize plants, we selected six fungicides (tebuconazole, difenoconazole, fluquinconazole, azoxystrobin, prochloraz and kresoxim-methyl) and examined their effectiveness against the two pathogens. The in vitro antifungal effects of the six fungicides on mycelial growth and colony formation were investigated. Based on the inhibition of mycelial growth, the most toxic fungicide was tebuconazole with 50% effective concentrations ($EC_{50}$) of < $0.1{\mu}g/ml$ and $EC_{90}$ values of $0.9{\mu}g/ml$ for both pathogens, while the least toxic fungicide was azoxystrobin with $EC_{50}$ values of 0.7 and $0.5{\mu}g/ml$ for F. subglutinans and F. temperatum, respectively, and $EC_{90}$ values of > $3,000{\mu}g/ml$ for both pathogens. Based on the inhibition of colony formation by the two pathogens, kresoxim-methyl was the most toxic fungicide with complete inhibition of colony formation at concentrations of 0.1 and $0.01{\mu}g/ml$ for F. subglutinans and F. temperatum, respectively, whereas azoxystrobin was the least toxic fungicide with complete inhibition of colony formation at concentrations > $3,000{\mu}g/ml$ for both pathogens.

• 치위생과학회지
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• 제18권1호
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• pp.60-68
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• 2018

This study investigates the relationship between smoking and periodontal disease through quantitative analysis of intra-buccal oral pathogenic bacteria detected in smokers and aims to yield objective baseline data for applications in anti-smoking and dental health education programs. From April to May 2016, participants in an oral health management program within an intensive dental hygiene training course at Choonhae College of Health Sciences received an explanation of the study purposes and methods, after which male smokers aged 18~30 years agreed to participate voluntarily. Real-time polymerase chain reaction (PCR) analysis of oral pathogenic bacteria was performed after collecting gingival sulcus fluid samples from 67 smokers. The intra-buccal oral pathogenic bacteria distributions were analyzed based on the subjects' general characteristics, smoking behaviors, and oral care behaviors. The distribution results show that pathogens in the anterior teeth are affected (in this order) by age, toothbrush size, and smoking status; older people had fewer pathogens, those who used larger toothbrushes had more pathogens, and smokers had more pathogens, compared to non-smokers ($_{adj}R^2=19.1$). In the posterior teeth, pathogens were influenced (in this order) by smoking status, smoking duration, and the number of tooth brushings per day; smokers had more pathogens than non-smokers, and those who brushed their teeth more often had fewer pathogens ($_{adj}R^2=25.1$). The overall pathogen distribution was affected only by smoking status: smokers generally had more pathogens, compared to non-smokers. Therefore, it is necessary to provide information about the risk of periodontal disease due to smoking during anti-smoking or dental health education sessions; particularly, the use of smaller toothbrushes for anterior teeth and the need for smokers in their early twenties to quit smoking for dental health should be highly emphasized.

• Parasites, Hosts and Diseases
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• 제53권5호
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• pp.653-659
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• 2015

The objective of this study was to investigate the prevalence of tick-borne pathogens in the Korean water deer (Hydropotes inermis argyropus). Pathogens were identified using PCR which included Anaplasma, Ehrlichia, Rickettsia, and Theileria. Rickettsia was not detected, whereas Anaplasma, Ehrlichia, and Theileria infections were detected in 4, 2, and 8 animals, respectively. The most prevalent pathogen was Theileria. Of the 8 Theileria-positive animals, 2 were mixed-infected with 3 pathogens (Anaplasma, Ehrlichia, and Theileria) and another 2 animals showed mixed-infection with 2 pathogens (Anaplasma and Theileria). Sequencing analysis was used to verify the PCR results. The pathogens found in this study were identified as Anaplasma phagocytophilum, Ehrlichia canis, and Theileria sp. To the best of our knowledge, this is the first report identifying these 3 pathogens in the Korean water deer. Our results suggest that the Korean water deer may serve as a major reservoir for these tick-borne pathogens, leading to spread of tick-borne diseases to domestic animals, livestock, and humans. Further studies are needed to investigate their roles in this respect.