• The Plant Pathology Journal
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• 제36권2호
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• pp.179-184
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• 2020

A leaf spot pathogen Alternaria sp. was recovered from jimson weed, tomato, parsley, and coriander collected during surveys of blight diseases on Solanaceae and Apiaceae in Algeria. This species produced large conidial body generating long apical beaks that tapered gradually from a wide base to a narrow tip and short conidiophores originating directly from the agar surface. This species exhibited morphological traits similar to that reported for Alternaria crassa. The identification of seven strains from different hosts was confirmed by sequence analyses at the glyceraldehyde-3-phosphate dehydrogenase, RNA polymerase second largest subunit, and translation elongation factor 1-alpha loci. Further the pathogen was evaluated on jimson weed, coriander, parsley, and tomato plants, and this fungus was able to cause necrotic lesions on all inoculated plants. A. crassa is reported for the first time as a new species of the Algerian mycoflora and as a new potential pathogen for cultivated hosts.

• 한국미생물·생명공학회지
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• 제47권2호
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• pp.289-295
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• 2019

Acute diarrhea is a global health problem that causes high morbidity and mortality in children. Notably, enteric pathogen co-infections have been suggested to play an important role in gastroenteritis. In this study, we analyzed 1150 stool specimens of patients who visited the pediatric ward of Dongguk University Hospital in Gyeongju province from January 2011 to December 2017. The average isolation rate of potential stool pathogens over 7 years was 37.3% (429/1150), and coinfections were observed in 51 patients (51/429; 11.9%). In the 51 co-infection cases, the most frequent type of co-infection was found to be that of virus-bacteria (33/51). The most frequently detected bacterial pathogen among the co-infected cases was Clostridium spp. (22/51), out of which Clostridium perfringens was found to be the main pathogen (16/22; 72.7%). Escherichia coli spp. were the second most common bacterial pathogens found in 12 cases (12/51; 23.5%), with 10 cases of E. coli EPEC. Furthermore, the most frequently implicated viral pathogen among the co-infected cases was norovirus (16/51), followed by rotavirus (12/51).

• Parasites, Hosts and Diseases
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• 제57권2호
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• pp.101-115
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• 2019

The pathogenesis of cerebral malaria is biologically complex and involves multi-factorial mechanisms such as microvascular congestion, immunopathology by the pro-inflammatory cytokine and endothelial dysfunction. Recent data have suggested that a pleiotropic T-cell immunomodulatory protein (TIP) could effectively mediate inflammatory cytokines of mammalian immune response against acute graft-versus-host disease in animal models. In this study, we identified a conserved homologue of TIP in Plasmodium berghei (PbTIP) as a membrane protein in Plasmodium asexual stage. Compared with PBS control group, the pathology of experimental cerebral malaria (ECM) in rPbTIP intravenous injection (i.v.) group was alleviated by the downregulation of pro-inflammatory responses, and rPbTIP i.v. group elicited an expansion of regulatory T-cell response. Therefore, rPbTIP i.v. group displayed less severe brain pathology and feverish mice in rPbTIP i.v. group died from ECM. This study suggested that PbTIP may be a novel promising target to alleviate the severity of ECM.

• Journal of Microbiology
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• 제41권2호
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• pp.144-147
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• 2003

Listeria monocytogenes is a pathogen of major concern to the food industry and the potential cause of severe infections such as listeriosis. Early detection of this foodborne pathogen is important in order to eliminate its potential hazards. So, immunomagnetic separation (IMS) has been suggested as a means of reducing the total analysis time and for improving the sensitivity of detection. Atomic force microscopy (AFM) has been used for measuring the topographic properties of sample surfaces at nanometer scale. In this study, we used AFM to confirm both the sensitivity and the specificity of IMS. Regarding AFM analysis, the length and the width of the bacteria, which were in agreement with literature values, were found to be 2.993 $\mu\textrm{m}$ and 0.837 $\mu\textrm{m}$, respectively. As a result, AFM helped us both characterize and measure the bacterial and bead structures.

• Mycobiology
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• 제36권4호
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• pp.242-248
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• 2008

The present study was undertaken to explore the inhibitory effect of cyanobacterial extracts of Nostoc commune FA-103 against the tomato-wilt pathogen, Fusarium oxysporum f. sp. lycopersici. In an optimal medium, cell growth, antifungal activity, and antifungal compound production could be increased 2.7-fold, 4.1-fold, and 13.4-fold, respectively. A crude algal extract had a similar effect as mancozeb at the recommended dose, both in laboratory and pot tests. In vitro and in vivo fungal growth, spore sporulation and fungal infection of wilt pathogen in tomato seeds were significantly inhibited by cyanobacterial extracts. Nostoc commune FA-103 extracts have potential for the suppression of Fusarium oxysporum f. sp. lycopersici.

• 한국식물병리학회지
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• 제10권1호
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• pp.61-63
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• 1994

A brown leaf and stem spot disease of bayonet-grass (Scirpus maritimus) was epidemic in reclaimed paddy fields of Chunbuk province, Korea. A fungal pathogen was repeatedly isolated from the necrotic lesions of the bayonet-grass and identified as Nimbya scirpicola. The pathogen induced disease symptoms only in bayonet-grass but not in 8 other plants tested; Brassica pathogen induced disease symptoms only in bayonet-grass but not in 8 other plants tested; Brassica compestris subsp. napus var. pekinensis, Cucumis sativus, Glycine max, Hordeum vulgare, Lycopersicon esculentum, Oryza sativa, Sesamum indicum and Triticum aestivum. The fungus has potential to be developed as a mycoherbicide.

• 현장농수산연구지
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• 제25권3호
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• pp.14-18
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• 2023

2022년 7월, 국내의 저염분 해수 흰다리새우 양식장에서 양식 중이던 흰다리새우가 이상유영과 식욕부진을 보이며 지속적으로 폐사하였다. 일일 평균 폐사율이 0.1%로 완만한 폐사를 보였으나, 2달 넘게 폐사가 지속되었고 성장 지체로 인한 경제적인 피해가 가중되었다. 질병 진단 과정 중, 폐사 새우의 간췌장에서 세균(KNUAF-SHP3)이 분리되었다. 본 세균의 16S rRNA 유전자의 시퀀스 분석 결과, 분리주 KNUAF-SHP3은 Shewanella에 속하는 균으로 동정이 되었고, S. algae MARS 14, S. chilikensis JC5T와 근연 관계를 보이며 같은 그룹으로 분류되었다. 실험 동물을 활용한 인위 감염 실험에서는 상대적으로 고농도(2.1×108CFU/ml와 2.1×109CFU/ml)를 적용한 군에서는 모든 새우들이 감염 증상을 보이며 감염 후 7일 내에 100% 폐사율을 나타내었다. 본 연구는 Shewanella 세균이 저염분 해수 양식 흰다리새우에서의 잠재적인 기회 감염균이 될 수 있음을 기술하고 있다.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2015년도 춘계학술대회 및 임시총회
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• pp.29-29
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• 2015

Clubroot disease is caused by the soil-born obligate plant pathogen Plasmodiophora brassicae. This pathogen can infect all cruciferous vegetables and oil crops, including Brassica rapa, B. oleracea, B. napus, and other Brassica species. Clubroot disease is now considered to be a major problem in Chinese cabbage production in China, Korea, and Japan. We collected several hundreds of P. brassicae infected galls from Korea, and isolated the single spore from the collection. For establishment of novel isolation, and mass-propagation methods for singe spore isolates of P. brassicae pathogen, we developed new filtration method using both cellulose nitrate filter and syringe filter. Accurate detection of P. brassicae pathogen in the field was done by using real-time PCR in the potential infested soil. When we tested the different pathogenicity on commercial Chinese cabbage varieties, P. brassicae from collected galls showed various morphological patterns about clubroot symptom on roots. To date, 8 CR loci have been identified in the B. rapa genome using the quantitative trait loci (QTL) mapping approach, with different resistant sources and isolates. We are trying to develop the molecular marker systems for detect all 8 CR resistant genes. Especially for the study on the interaction between pathogens and CR loci which are not well understood until now, genome wide association studies are doing using the sequenced inbred lines of Chinese cabbage to detect the novel CR genes.

• Journal of Microbiology and Biotechnology
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• 제29권6호
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• pp.887-896
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• 2019

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS)-based pathogen identification relies on the ribosomal protein spectra provided in the proprietary database. Although these mass spectra can discern various pathogens at species level, the spectra-based method still has limitations in identifying closely-related microbial species. In this study, to overcome the limits of the current MALDI-TOF MS identification method using ribosomal protein spectra, we applied MALDI-TOF MS of low-mass profiling to the identification of two genetically related Bacillus species, the food-borne pathogen Bacillus cereus, and the insect pathogen Bacillus thuringiensis. The mass spectra of small molecules from 17 type strains of two bacilli were compared to the morphological, biochemical, and genetic identification methods of pathogens. The specific mass peaks in the low-mass range (m/z 500-3,000) successfully identified various closely-related strains belonging to these two reference species. The intensity profiles of the MALDI-TOF mass spectra clearly revealed the differences between the two genetically-related species at strain level. We suggest that small molecules with low molecular weight, 714.2 and 906.5 m/z can be potential mass biomarkers used for reliable identification of B. cereus and B. thuringiensis.

• Journal of Ginseng Research
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• 제38권2호
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• pp.136-145
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• 2014

Background: This study aimed to develop a biocontrol system for ginseng root rot caused by Fusarium cf. incarnatum. Methods: In total, 392 bacteria isolated from ginseng roots and various soils were screened for their antifungal activity against the fungal pathogen, and a bacterial isolate (B2-5) was selected as a promising candidate for the biocontrol because of the strong antagonistic activity of the bacterial cell suspension and culture filtrate against pathogen. Results: The bacterial isolate B2-5 displayed an enhanced inhibitory activity against the pathogen mycelial growth with a temperature increase to $25^{\circ}C$, produced no pectinase (related to root rotting) an no critical rot symptoms at low [$10^6$ colony-forming units (CFU)/mL] and high ($10^8CFU/mL$) inoculum concentrations. In pot experiments, pretreatment with the bacterial isolate in the presumed optimal time for disease control reduced disease severity significantly with a higher control efficacy at an inoculum concentration of $10^6CFU/mL$ than at $10^8CFU/mL$. The establishment and colonization ability of the bacterial isolates on the ginseng rhizosphere appeared to be higher when both the bacterial isolate and the pathogen were coinoculated than when the bacterial isolate was inoculated alone, suggesting its target-oriented biocontrol activity against the pathogen. Scanning electron microscopy showed that the pathogen hyphae were twisted and shriveled by the bacterial treatment, which may be a symptom of direct damage by antifungal substances. Conclusion: All of these results suggest that the bacterial isolate has good potential as a microbial agent for the biocontrol of the ginseng root rot caused by F. cf. incarnatum.