• Research in Plant Disease
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• v.24 no.1
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• pp.81-85
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• 2018

Chinese artichoke (Stachys sieboldii Miq.) belongs to herbaceous perennial plants of Labiatea and is cultivated as edible and medicinal crops in China, Japan and Korea. A Chinese artichoke plant showing virus-like symptoms was collected in Chungju, Korea. Plant sap of the sample was inoculated in Nicotiana tabacum cv. Xanthi-nc, Chenopodium quinoa and Chenopodium amaranticolor. Necrotic local lesions were observed in the inoculated leaves of N. tabacum cv. Xanthi-nc and C. amaranticolor, C. quinoa with systemic chlorotic spots and mosaic symptoms on the upper leaves. The disease reactions on indicator plants suggested that the collected Chinese artichoke sample was mixed-infected with different viruses. We detected three viruses by RT-PCR analysis using genus- and species-specific primer sets for Alfalfa mosaic virus (AMV), Cucumber mosaic virus (CMV) and Tobacco mosaic virus (TMV). This study is the first report of a mixed infection of three viruses in Chinese artichoke in Korea.

• Parasites, Hosts and Diseases
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• v.35 no.2
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• pp.127-134
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• 1997

Transmission electron microscopy of an ArGnthnmoebo isolate (KA/LS) from a contact lens case revealed bacterial endosymbionts within cytoplasm of the amoebae. The Acnnthamoebn isolate belonged to the morphological group ll. Based on the polymerase chain reaction (PCR) - restriction fragment leilgth polymorphism (RFLP) of 185 ribosomal RNA coding DNA (rDNA) , the isolate was identified as A. Iwnunensis. Strain typing by isoenzyme analysis using isorlectric focusing (IEF) and mitochondrial (Ent) DNA RFLP revealed that the isolate was closely related with KA/Ll , the most predominant type of isolates from contact lens storage casas, KA/E2, a clinical isolate, KA/W4, previou:fly reported to host endosymbionts. and L3a strains of A. Iwnunensis. The endosymbionts were similar to those of KA/W4 in a.jpects that they were randomly distributed in both trophozoites and cysts, and were rod-shaped bacteri3 measuring approximately 1.38 x 0.50 ㎛. But the number of endosymbionts per amoeba was significantly lower than that of KA/W4. They were neither limited by phagosomal membranes nor included in lacunae- like stnlcture.

• The Korean Journal of Food And Nutrition
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• v.27 no.2
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• pp.213-218
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• 2014

The enterotoxin production and antimicrobial susceptibility on hemolytic strains from stools of diarrheal pigs was investigated in this study. Through morphological observation, gyrB nucleotide sequence, and API kit analysis, the selected potential pathogenic strain BY06 was identified as Bacillus cereus. Because the characteristic of enterotoxin symptoms were widely caused by Bacillus cereus strains, a PCR test was carried out in order to check the enterotoxin genes (hblA) in this strain. According to the results, this strain was an enterotoxin positive strain containing the hblA gene. The minimum inhibitory concentrations of 10 different antimicrobial agents were screened by the agar dilution test, indicating that this strain was resistant to penicillin G and intermediate to erythromycin; however, it susceptible to cephalothin, vancomycin, clindamycin, fusidic acid, gentamicin, ciprofloxacin, tetracycline and rifampin. These results suggest that the B. cereus BY06 isolated from pig feces has a potential risk of producing enterotoxin and is resistant to penicillin G, but susceptible to various antimicrobial agents.

• Restorative Dentistry and Endodontics
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• v.28 no.2
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• pp.178-183
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• 2003

The purpose of this study was to investigate the frequency of 7 putative pathogens in endodontic infections. The specimens were collected from infected pulpal tissue of patients who were referred for root canal treatment to the department of conservative dentistry, Chosun University Samples were collected aseptically using a barbed broach and a paper point. The cut barbed broaches and paper points were transferred to an eppendorf tube containing 500 ml of 1 X PBS. DNAs were extracted from the samples by direct DNA extraction method using lysis buffer (0.5% EDTA, 1% Triton X-100). Identification of 7 putative pathogens was performed by PCR based on 16S rDNA. The target species were as follows : Porphyromonas endodontalis, Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens, Bacteroides forsythus, Actinobacillus actinomycetemcomitans, and Treponema denticola. Our data revealed that the prevalence of P. endodontalis was found in 88.6% (39/54), P. ginivalis 52.3% (23/44), P. nigrescens 18.2% (8/44), P intermedia 15.9% (7/44) B. forsythus 18.2% (8/44), A. actinomycetemcomitans 3.3% (1/44), T. denticola 25% (l1/44) of the samples. The high prevalence of P. endodontalis and P. ginivalis suggests that they may play an important role in the etiology of endodontic infections.

• Research in Plant Disease
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• v.14 no.1
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• pp.15-20
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• 2008

Three isolates of Cucumber mosaic virus (CMV) were isolated from weed hosts showing typical mosaic symptoms, and some properties of the viruses were investigated. CMV isolates, designated as Is-CMV, Jd-CMV and Pla-CMV from Isodon inflexus, Jeffersonia dubia and Phryma leptostachya var. asiatica, respectively, were identified and characterized by biological reaction in several host plants, serological property, dsRNA analysis, reverse transcription-polymerase chain reaction (RT-PCR), restriction fragment-length polymorphism (RFLP). All isolates systemically infected in Nicotiana benthamiana, Cucurbita pepo cv. Black beauty and Cucumis sativus, and did not reveal any differences in these host plants between the isolates. However, remarkable difference in the symptoms was found between the CMVs in Capsicum annuum. Is-CMV induced an asymptomatic symptoms, while Jd-CMV and Pla-CMV produced severe mosaic symptoms in C. annuum plants. In dsRNA analysis, all isolates revealed four major bands with estimated molecular size of 3.4, 3.2, 2.1 and 1.0 kbp. The cDNAs of coat protein gene of the isolates were amplified by RT-PCR using a genus-specific single pair primers that designed to amplify a DNA fragment of approximately ranging from 938 to 966 bp. By restriction mapping analysis using RFLP of the RT-PCR products as well as by serological properties of gel diffusion test, the CMV isolates belong to a typical members of CMV subgroup IA. This is the first report on the occurrence of CMV in the three weed hosts.

• Research in Plant Disease
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• v.17 no.1
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• pp.66-74
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• 2011

In 2005, a survey was conducted to identify virus diseases on victory onion, Allium victorialis var. platyphyllum grown in Ulleung island located in the East Sea. A total of 61 samples were collected from victory onion in the neighborhood of Seonginbong. The identification of viruses from the samples were carried out by electron microscopy and RT-PCR using primers species specific to GCLV, LYSV, SLV, OYDV and genus specific to Allexivirus, respectively. From sixty-one samples, filamentous rod particles (600-900 nm) were detected from four victory onion samples in EM, three samples containing SLV and one sample containing both SLV and Allexivirus in RT-PCR analysis, respectively. Victory onions naturally infected by the viruses were asymptomatic apparently. The viruses detected by RT-PCR were further characterized by the nucleotide sequence analysis of the coat protein region. Three isolates of SLV showed approximately 99% identities in the nucleotide and amino acid sequences, suggesting that they were likely to be the same strain. On the other hand, they showed approximately 75.7~83.7% identities in the nucleotide and 89.2~97.0% in amino acid sequences compared with the previously reported SLV isolates in Allium. The CP gene of the Allexivirus showed approximately 99.2% nucleotide identities and 98.8% amino acid identities with Garlic virus A. However, there was relatively low homology ranging from 60.6% to 81.5% compared with other Allexiviruses (GarV-C, GarV-E, GarV-X, GMbMV, and Shal-X). These data suggested that two viruses, SLV and GarV-A identified from victory onion, are named SLV-Ulleungdo and GarV-A-Ulleungdo, respectively. This is the first report of viruses infecting victory onion.

• Journal of Veterinary Clinics
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• v.31 no.3
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• pp.194-198
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• 2014

Methicillin-resistant staphylococci (MRS) are emerging as important pathogens in humans and animals worldwide. The aim of this study was to investigate the prevalence of MRS in the racehorse population and in horse-related personnel in Korea. A total of 195 horses and 18 humans (eight veterinarians, three veterinary hospital staff, and seven horse-handlers) from racehorse farms in Korea were included in the study. The samples were collected from nasal cavities using bacterial transport medium and were cultivated on tryptic soy agar with 5% sheep blood for 3 days at $37^{\circ}C$ to confirm the presence of Staphylococcus spp. Presumptive Staphylococcus spp. isolates were identified by 16S ribosomal RNA gene analysis. The coagulase test and oxacillin susceptibility tests were performed using the tube dilution and disk diffusion methods, respectively. The presence of the mecA gene was determined using a polymerase chain reaction assay. Of the 195 horses, 29 (15.6%) yielded 29 MRS isolates. Twelve (66.7%) of the 18 horse-related personnel yielded 12 MRS isolates. All of the MRS isolates from horses or horse-related personnel were identified as methicillin-resistant coagulase-negative staphylococci (MRCNS). The result of this study suggest that the prevalence of MRS increased with the duration of antibiotic use (p = 0.002). This study also provides evidence for the zoonotic transmission of MRCNS between horses and humans, although further investigations are needed.

• Journal of Life Science
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• v.31 no.1
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• pp.10-16
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• 2021

The consumption of fresh-cut agricultural materials is increasing due to increased public interest in health and the increase of single-person households. Most fresh-cut agricultural materials can be eaten without heating, thus easily exposing the consumer to food-borne pathogens. As a result, food-borne diseases are increasing worldwide. In the analysis of food-borne pathogens, it is important to detect the strains, but this is time consuming and laborious. Alternative detection methods that have been introduced, include polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE), which is performed without prior culturing. Samples of fresh-cut agricultural materials, such as vegetables, were analyzed by the culture-based method. In 129 samples, non-pathogenic Escherichia coli (3.9%), Bacillus cereus (31.8%), Clostridium perfringens (5.4%), Yersinia enterocolitica (0.8%), and enterohemorrhagic E. coli (0.8%) were detected. Eight samples contaminated with bacteria were randomly selected, further analyzed by PCR-DGGE, and compared with the culture-based method. Two cases detected non-pathogenic E. coli by PCR-DGGE only, despite a lack of detection by the culture method. It was supposed there was possibility of sample loss during its 10-fold dilution for appropriate cultivation. In the detection of high-risk food-borne pathogens, it was found that the detection limit was lower in PCR-DGGE than in the culture-based method (10 CFU/g). This suggests that PCR-DGGE can be alternatively used to detect strains. On the other hand, low-risk food-borne pathogens seem to have higher detection limits in PCR-DGGE. Consequentially, this study contributes to the improvement of food-borne pathogen detection and the prevention of its related-diseases in fresh-cut agricultural materials.

• Research in Plant Disease
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• v.12 no.3
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• pp.205-212
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• 2006

Agrobacterium vitis is a causal agent of crown-gall disease on grapevine. Bacterial strains were isolated from crown galls of different grapevine varieties in grapevine farms of Kyungbuk(Kimcheon), Chungbuk(Okcheon), Chungnam(Daejon, Choenan) and Kyeonggi(Suwon, Ansung) areas in Korea from 2002 to 2005. Primer sets, Phe A and VirA, which were derived from pectate lysase gene and virA gene of Ti-plasmid in A. vitis were used to detect A. vitis strains from crown galls. PheA and VirA primers amplified DNA fragments of 0.25 kb and 0.5 kb from fifty-one bacterialstrains. They formed crown galls on grapevine variety, Kyoho, or carrot disks with variable pathgenecity It was confirmed that the biochemical characteristics of 10 bacterial strains that was strong pathogene city on grapevine were mostly in agreement with type culture strains of A. vitis, showing growth in the presence of 2% NaCl, non-production of acid from melezitose and negative response in production of 3-Ketolactose.

• Research in Plant Disease
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• v.8 no.2
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• pp.92-100
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• 2002

For the survey of viruses infected in peanut cultivated in Korea, peanut seeds and leaves showing viral symptoms were collected from their growing areas. Typical symptoms on virus infected peanut leaves including mosaic, mottle with necrosis, yellowing, stripe or vein banding and stunts were observed. Two viruses isolated from the naturally infected peanuts were identified as Bean common mosaic virus(BCMV-PSt) and Peanut mottle virus(PeMoV) by their host range, immunosorbent elcetron microscopy(ISEM), direct immuno staining assay(DISA), RT-PCR, and intracellural symptoms. Direct negative staining method by electron microscope showed filamentous particles of about 780 m in length as well as inclusion bodies. In ultrathin sections of BCMV-PSt and PeMoV infected tissues, cytoplasmic cylindrical inclusions as well as filamentous virus particles were observed in the cytoplasm of parenchyma cells. ISEM revealed filamentous particles strongly decorated with antiserums of BCMV-PSt and PeMoV Peanut seeds were stained with BCMV-PSt and PeMoV antisera indicating the possibility of seed transmission far these viruses. Seedlings germinated from peanut seeds which reacted with antiserums of BCMV-PSt by DISA showed mild mottle or stripe symptoms while mosaic and necrotic mottle symptoms were observed for PeMoV-positive seedlings. Filamentous particles were strongly decorated with each antiserum under ISEM observation. BCMV-PSt coat protein gene of about 1.2 Kbp was amplified by RT-PCR. Altogether these results indicate that BCMV-PSt is the most prevalent virus infecting peanut in Korea.