• Journal of Microbiology and Biotechnology
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• v.21 no.12
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• pp.1352-1355
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• 2011

Forty-one Enterococcus faecalis (E. faecalis) isolates from feces of pigs and chickens in Korea were screened for the presence of virulence factors. Gelatinase activity (85.4%, 35/41) was the more commonly observed phenotype of virulence in E. faecalis, compared with hemolytic activity (12.2%, 5/41). Thirty-one of 35 (88.6%) gelatinase-positive E. faecalis isolates harbored the gelE and fsrABC genes. A gene encoding for the enterococcal surface protein (Esp) was detected in 24.4% (10/41) of the isolates. All beta-hemolysin-producing isolates harbored the esp gene.

• Journal of environmental and Sanitary engineering
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• v.15 no.4
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• pp.105-113
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• 2000

We have isolated 65 strains(2.0%) of Y. enterocolitica among 3,219 water samples from 380 spring water sites in Seoul from 1994 to 1999. The biochemical characteristics of isolated strains revealed that TSI was A/A, urea, M.R.($37^{\circ}C$), nitrate, motility($37^{\circ}C$), sorbitol, maltose, manitol, arabinose, mannose, trehalose, xylose were positive(100%) and H$_2$S, arginine, lysine, oxidase, citrate, V.P.($37^{\circ}C$), DNase, motility($37^{\circ}C$), dulcitol, adonitol, lactose and raffinose were negative(100%). In in vitro virulence test, positive rate of AAG and CRMOX were 9.2% and 4.6%, respectively. However in the virulence gene detectable gene detectable test by multiplex-PCR using ail, yst, virF genes, 65 strains were all negative, meaning that Y.enterocolitica strains from domestic spring water were not detected for the virulence. Otherwise, mutiplex-PCR which using ail, yst and subgenus-specific primer pair was the best for identifying the virulence of Y. enterocolitica.

• The Plant Pathology Journal
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• v.36 no.1
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• pp.29-42
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• 2020

Acidovorax citrulli causes bacterial fruit blotch in Cucurbitaceae, including watermelon. Although A. citrulli is a seed-borne pathogen, it can cause diverse symptoms in other plant organs like leaves, stems and fruits. To determine the infection routes of A. citrulli, we examined the virulence of six isolates (Ac0, Ac1, Ac2, Ac4, Ac8, and Ac11) on watermelon using several inoculation methods. Among six isolates, DNA polymorphism reveals that three isolates Ac0, Ac1, and Ac4 belong to Clonal Complex (CC) group II and the others do CC group I. Ac0, Ac4, and Ac8 isolates efficiently infected seeds during germination in soil, and Ac0 and Ac4 also infected the roots of watermelon seedlings wounded prior to inoculation. Infection through leaves was successful only by three isolates belonging to CC group II, and two of these also infected the mature watermelon fruits. Ac2 did not cause the disease in all assays. Interestingly, three putative type III effectors (Aave_2166, Aave_2708, and Aave_3062) with intact forms were only found in CC group II. Overall, our results indicate that A. citrulli can infect watermelons through diverse routes, and the CC grouping of A. citrulli was only correlated with virulence in leaf infection assays.

• Mycobiology
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• v.50 no.6
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• pp.467-474
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• 2022

Autophagy serves as a survival mechanism and plays important role in nutrient recycling under conditions of starvation, nutrient storage, ad differentiation of plant pathogenic fungi. However, autophagy-related genes have not been investigated in Colletotrichum scovillei, a causal agent of pepper fruit anthracnose disease. ATG8 is involved in autophagosome formation and is considered a marker of autophagy. Therefore, we generated an ATG8 deletion mutant, ΔCsatg8, via homologous recombination to determine the functional roles of CsATG8 in the development and virulence of C. scovillei. Compared with the wild-type, the deletion mutant ΔCsatg8 exhibited a severe reduction in conidiation. Conidia produced by ΔCsatg8 were defective in survival, conidial germination, and appressorium formation. Moreover, conidia of ΔCsatg8 showed reduced lipid amount and PTS1 selectivity. A virulence assay showed that anthracnose development on pepper fruits was reduced in ΔCsatg8. Taken together, our results suggest that CsATG8 plays various roles in conidium production and associated development, and virulence in C. scovillei.

• The Plant Pathology Journal
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• v.39 no.1
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• pp.62-74
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• 2023

Plant pathogenic Pectobacterium species cause severe soft rot/blackleg diseases in many economically important crops worldwide. Pectobacterium utilizes plant cell wall degrading enzymes (PCWDEs) as the main virulence determinants for its pathogenicity. In this study, we screened a random mutant, M29 is a transposon insertion mutation in the metC gene encoding cystathionine β-lyase that catalyzes cystathionine to homocysteine at the penultimate step in methionine biosynthesis. M29 became a methionine auxotroph and resulted in growth defects in methionine-limited conditions. Impaired growth was restored with exogenous methionine or homocysteine rather than cystathionine. The mutant exhibited reduced soft rot symptoms in Chinese cabbages and potato tubers, maintaining activities of PCWDEs and swimming motility. The mutant was unable to proliferate in both Chinese cabbages and potato tubers. The reduced virulence was partially restored by a complemented strain or 100 µM of methionine, whereas it was fully restored by the extremely high concentration (1 mM). Our transcriptomic analysis showed that genes involved in methionine biosynthesis or transporter were downregulated in the mutant. Our results demonstrate that MetC is important for methionine biosynthesis and transporter and influences its virulence through Pcc21 multiplication in plant hosts.

• Pediatric Infection and Vaccine
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• v.22 no.3
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• pp.194-200
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• 2015

Purpose: Urinary tract infection (UTI) is a common bacterial infection in children and Escherichia coli is a predominant pathogen. The purpose of this study is to evaluate phylogenetic groups and virulence factors of E. coli causing UTI in children in Korea. Methods: From October 2010 to April 2013, urinary E. coli strains were isolated from the 33 pediatric patients of UTI. Multiplex polymerase chain reactions were performed to evaluate the phylogenetic groups and 5 virulence factor genes (fimH, sfa, papA, hylA, and cnf1) of E. coli. Distribution of molecular characteristics of E. coli was analyzed by clinical diagnosis and accompanying vesicoureteral reflux (VUR). Results: Most (84.8%) uropathogenic E. coli were belonged to phylogenetics group B2 and the others (15.2%) were belonged to group D. The virulence factors were distributed as: fimH (100%), sfa (100%), hylA (63.6%), cnfI (63.6%), and papA (36.4%). According to clinical diagnosis, phylogenetic distribution of E. coli strain was 92.3% of B2 and 7.7% of D in acute pyelonephritis and 57.1% of B2 and 42.9% of D in cystitis. Distribution of virulence factors was similar in both groups. In patients with acute pyelonephritis, phylogenetic distribution was similar in VUR and non-VUR group, but proportion of papA genes were lower in VUR group than that of non-VUR group (43.8% vs. 20.0%, P=0.399). Conclusions: This study provides current epidemiologic molecular data of E. coli causing pediatric UTI in Korea and will be a fundamental for understanding the pathogenesis of pediatric UTI.

• Microbiology and Biotechnology Letters
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• v.33 no.3
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• pp.207-214
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• 2005

To characterize the genotypic traits of clinical methicillin-resistant Staphyiococus aureus (MRSA) isolates (n=49), major virulence-associated genes were detected by using PCR-based methods. All the MRSA isolates possessed coagulase gene and showed four polymorphism types [500bp ($6{\%}$),580bp ($27{\%}$), 660bp ($65{\%}$) and 740bp ($2{\%}$)] due to variable numbers of tandem repeats present within the gene. The four or five different loci of hemolysin gene family were dominant in the MRSA isolates,25 of which($51{\%}$) possessed a combination of hla / hlb / hld/ hlg / hlg-2 genes as the most prevalent type. The prevalence of enterotoxin genes was varied among the MRSA isolates. sea and seb genes were detected from all the MRSA isolates. But sei, tsst-1, seg, sec, and seh genes were detected from 31 ($63{\%}$), 16 ($33{\%}$), 14 ($29{\%}$), 8 ($16{\%}$), and 5 ($10{\%}$) isolates, respectively. sed and sej genes were detected from 1 ($2{\%}$) isolate, respectively. see, eta, and etb genes were not detected at all. sea / seb genes were co-detected from 11 ($23{\%}$) isolates, sea / seb / sei genes from 9 ($19{\%}$) isolates, and sea / seb / seg / sei / tsst-1 genes from 5 ($10{\%}$) isolates. Other genes were co-detected with below $10{\%}$ frequencies.

• Mycobiology
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• v.46 no.4
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• pp.361-369
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• 2018

The rice blast fungus, Magnaporthe oryzae, is an important pathogen of rice plants. It is well known that genes encoded in the genome have different evolutionary histories that are related to their functions. Phylostratigraphy is a method that correlates the evolutionary origin of genes with evolutionary transitions. Here we applied phylostratigraphy to partition total gene content of M. oryzae into distinct classes (phylostrata), which we designated PS1 to PS7, based on estimation of their emergence time. Genes in individual phylostrata did not show significant biases in their global distribution among seven chromosomes, but at the local level, clustering of genes belonging to the same phylostratum was observed. Our phylostrata-wide analysis of genes revealed that genes in the same phylostratum tend to be similar in many physical and functional characteristics such as gene length and structure, GC contents, codon adaptation index, and level of transcription, which correlates with biological functions in evolutionary context. We also found that a significant proportion of genes in the genome are orphans, for which no orthologs can be detected in the database. Among them, we narrowed down to seven orphan genes having transcriptional and translational evidences, and showed that one of them is implicated in asexual reproduction and virulence, suggesting ongoing evolution in this fungus through lineage-specific genes. Our results provide genomic basis for linking functions of pathogenicity factors and gene emergence time.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2005.04a
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• pp.84-85
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• 2005

• Proceedings of the Korean Society of Life Science Conference
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• 2008.10a
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• pp.73.2-73.2
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• 2008