• 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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• 제28권4호
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• pp.364-372
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• 2012

Xanthomonas oryzae pv. oryzae causing bacterial leaf blight disease in rice produces and secretes Hpa1 protein that belongs to harpin protein family. Previously it was reported that Hpa1 induced defense responses when it was produced in tobacco. In this study, we expressed hpa1 gene in rice and Arabidopsis to examine the effects of Hpa1 expression on disease resistance to both fungal and bacterial pathogens. Expression of hpa1 gene in rice enhanced disease resistance to both X. oryzae pv. oryzae and Magnaporthe grisea. Interestingly, individual transgenic rice plants could be divided into four groups, depending on responses to both pathogens. hpa1 expression in Arabidopsis also enhanced disease resistance to both Botrytis cineria and Xanthomonas campestris pv. campestris. To examine genes that are up-regulated in the transgenic rice plants after inoculation with X. oryzae pv. oryzae, known defense-related genes were assessed, and also microarray analysis with the Rice 5 K DNA chip was performed. Interestingly, expression of OsACS1 gene, which was found as the gene that showed the highest induction, was induced earlier and stronger than that in the wild type plant. These results indicate that hpa1 expression in the diverse plant species, including monocot and dicot, can enhance disease resistance to both fungal and bacterial plant pathogens.

• The Plant Pathology Journal
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• 제30권2호
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• pp.125-135
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• 2014

A population model of bacterial spot caused by Xanthomonas campestris pv. vesicatoria on hot pepper was developed to predict the primary disease infection date. The model estimated the pathogen population on the surface and within the leaf of the host based on the wetness period and temperature. For successful infection, at least 5,000 cells/ml of the bacterial population were required. Also, wind and rain were necessary according to regression analyses of the monitored data. Bacterial spot on the model is initiated when the pathogen population exceeds $10^{15}cells/g$ within the leaf. The developed model was validated using 94 assessed samples from 2000 to 2007 obtained from monitored fields. Based on the validation study, the predicted initial infection dates varied based on the year rather than the location. Differences in initial infection dates between the model predictions and the monitored data in the field were minimal. For example, predicted infection dates for 7 locations were within the same month as the actual infection dates, 11 locations were within 1 month of the actual infection, and only 3 locations were more than 2 months apart from the actual infection. The predicted infection dates were mapped from 2009 to 2012; 2011 was the most severe year. Although the model was not sensitive enough to predict disease severity of less than 0.1% in the field, our model predicted bacterial spot severity of 1% or more. Therefore, this model can be applied in the field to determine when bacterial spot control is required.

• The Plant Pathology Journal
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• 제23권1호
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• pp.22-25
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• 2007

Biocontrol activity of five strains of selected rhizo-bacteria were tested in tomato against bacterial wilt caused by Ralstonia solanacearum. After root bacterization the plants were grown in a perlite-hydroponic system. Upon challenge inoculation with the pathogen, all of the rhizobacterial strains efficiently suppressed the bacterial wilt in tomato in various rates, at maximum by the strain, Bacillus vallismortis strain EXTN-1. While the percent of infected plants in the non-bacterized control plants were 95%, it was only 65% in plants pre-treated with EXTN-1. It was also demonstrated that the movement of R. solanacearum within the stem was significantly hampered when the plants were root bacterized. As EXTN-1 has no antagonistic properties against R. solanacearum, the bacterial wilt was probably suppressed by a mechanism other than antibiosis. Previously, the strain had been proven to produce an efficient elicitor for inducing systemic resistance in many crops. As the present study confirmed that EXTN-1 has the ability for reducing the pathogen spread in tomato, the strain could be effectively used as a potential biocontrol agent against bacterial wilt.

• The Plant Pathology Journal
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• 제20권1호
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• pp.7-12
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• 2004

An important recent advance in the field of plant-microbe interactions has been the cloning of genes that confer resistance to specific viruses, bacteria, fungi or insects. Disease resistance (R) genes encode proteins with predicted structural motifs consistent with them having roles in signal recognition and transduction. Plant disease resistance is the result of an innate host defense mechanism, which relies on the ability of plant to recognize pathogen invasion and efficiently mount defense responses. In tomato, resistance to the pathogen Pseudomonas syringae pv. tomato is mediated by the specific recognition between the tomato serine/threonine kinase Pto and bacterial protein AvrPto or AvrPtoB. This recognition event initiates signaling events that lead to defense responses including an oxidative burst, the hypersensitive response (HR), and expression of pathogenesis- related genes.

• 한국유기농업학회지
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• 제6권1호
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• pp.35-43
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• 1997

For the purpose of acquiring microbial agents that can be utilized to billogically control the major airborne disease to apple trees, such as canker(Valsa ceratosperma), the effective microorgaisms were isolated, tested for antagonistic activity to the pathogen causing major disease to apple trees and identifed. Screening of more than 3, 000 species of microorganisms collected in nature for them antagonistic action to the pathogen, Valsa ceratosperma causing disease to apple tree resulted in selection of effective species. Out of the 11 species, one species designated as CAP141 demonstrated outstanding activity. The bacterial strain, CAP141 exerted antagonistic efficiency of 65% on Valsa ceratosperma. The CAP141 was identified as a bacterial strain to Bacillus subtilis based on morphology, culture conditions, and physio-biochemical characteristics.

• Journal of Microbiology and Biotechnology
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• 제26권8호
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• pp.1343-1347
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• 2016

Outer membrane vesicles (OMVs) are spherical nanostructures that are ubiquitously shed from gram-negative bacteria both in vitro and in vivo. Recent findings revealed that OMVs, which contain diverse components derived from the parent bacterium, play an important role in communication with neighboring bacteria and the environment. Furthermore, nanoscale proteoliposomes decorated with pathogen-associated molecules attract considerable attention as a non-replicative carrier for vaccines and drug materials. This review introduces recent advances in OMV biogenesis and discusses the roles of OMVs in the context of bacterial communication and virulence regulation. It also describes the remarkable accomplishments in OMV engineering for diverse therapeutic applications.

• Applied Biological Chemistry
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• 제48권3호
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• pp.296-300
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• 2005

Among the root colonizing and plant growth promoting bacteria isolated from the bacterial wilt suppressive soil, five strains were detected to produce siderophores by CAS agar assay. The most effective isolate, TS3-7 strain induced significant suppression of bacterial wilt disease in tomato and pepper plants. Seed treatment followed by soil drench application with this strain resulted in over 80% reduction of bacterial wilt disease compared with the control. Significant disease suppression by TS3-7 strain was related to the production of siderophore. Besides iron competition, induction of resistance of the host plant with siderophore was suggested to be another mode of action that suppress bacterial wilt, based on the lack of direct antibiosis against pathogen in vitro. According to Bergey's Manual of Systemic Bacteriology and 16S rDNA sequence data, TS3-7 stain was identified as Pseudomonas sp. TS3-7.

• 식물병연구
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• 제29권1호
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• pp.39-44
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• 2023

To diagnose lily fasciation, lily bulbs showing fasciation were collected from several greenhouses in Jeju Island, South Korea. Bacteria were isolated from the lily bulbs and amplified with both primers for fasA in plasmid and for putative glycosyltransferase epsH gene in chromosome of Rhodococcus fascians. Three bacterial isolates were detected with the P450 primer set and identified as R. fascians by NCBI blast analysis. Twelve bacterial isolates were identified as R. fascians using RS02785 primer set, including the three bacterial isolates identified as the same pathogen using the P450 primer set. Pathogenicity of these bacterial strains identified as R. fascians was demonstrated. Apparent symptoms were observed on wounded lily leaves after inoculation with each bacterial suspension whereas no symptom was found on lily leaves treated with H₂O. Furthermore, bacteria re-isolated from wounded sites were identified as R. fascians. Based on the results, these two sets of primers are recommended for quarantine of R. fascians.

• Journal of Microbiology and Biotechnology
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• 제24권6호
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• pp.732-739
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• 2014

We describe the development of a polymerase chain reaction method for the rapid, precise, and specific detection of the Xanthomonas oryzae pv. oryzae (Xoo) K3a race, the bacterial blight pathogen of rice. The specific primer set was designed to amplify a genomic locus derived from an amplified fragment length polymorphism specific for the K3a race. The 1,024 bp amplicon was generated from the DNA of 13 isolates of Xoo K3a races out of 119 isolates of other races, pathovars, and Xanthomonas species. The assay does not require isolated bacterial cells or DNA extraction. Moreover, the pathogen was quickly detected in rice leaf 2 days after inoculation with bacteria and at a distance of 8 cm from the rice leaf 5 days later. The results suggest that this PCR-based assay will be a useful and powerful tool for the detection and identification of the Xoo K3a race in rice plants as well as for early diagnosis of infection in paddy fields.