• The Plant Pathology Journal
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• v.32 no.1
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• pp.65-69
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• 2016

In plant virus ecology, weeds are regarded as wild reservoirs of viruses and as potential sources for insect-mediated transmission of viruses. During field surveys in 2013-2014, three Leonurus sibiricus plants showing virus-like symptoms were collected from pepper fields in Daegu, Seosan, and Danyang in Korea. Molecular diagnosis assays showed that the collected L. sibiricus samples were infected with either Tomato spotted wilt virus (TSWV), Pepper mild mottle virus (PMMoV), or Beet western yellow virus (BWYV), respectively. Since this is the first identification of TSWV, PMMoV, and BWYV from L. sibiricus, complete genome sequences of three virus isolates were determined to examine their phylogenetic relationships with the previously reported strains and isolates. Phylogenetic analyses performed using full genome sequences of the viruses showed the isolates of TSWV and PMMoV obtained from L. sibiricus are closely related to the pepper isolates of the corresponding viruses. Our results suggest that L. sibiricus could act an alternative host and reservoir of viruses that cause damages in pepper fields.

• Korean Journal of Microbiology
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• v.53 no.2
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• pp.144-145
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• 2017

A Bacillus subtilis strain, designated G24, was isolated from grape during a study on the fermentation of Cheongkukjang, Korean traditional fast-fermented bean paste. Also, a newly isolated bacteriophage SPG24, which was found to inhibit the fermentation process, uses B. subtilis G24 as a host. The complete genome sequence of the bacteriophage SPG24 was 152,060 bp in length, with a G+C content of 42.2%. This sequence included 232 ORF; 58 forward ORFs and 174 reverse ORFs.

• Korean Journal of Microbiology
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• v.54 no.1
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• pp.79-80
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• 2018

Citrobacter freundii is a facultative anaerobic and a Gram-negative bacterium of Enterobacteriaceae family, and is an opportunistic pathogen. Bacteriophages infecting C. freundii can be an effective treatment for C. freundii infections. Here, the complete genomic sequence is announced for a lytic bacteriophage CF1 infecting C. freundii isolates.

• Journal of Microbiology and Biotechnology
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• v.27 no.12
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• pp.2151-2155
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• 2017

Bacteriophages have gained substantial attention as biocontrol and biorecognition agents, substituting antibodies. In this study, a Salmonella Enteritidis-specific bacteriophage, KFS-SE1, was isolated, identified, and characterized. This Siphoviridae phage infects S. Enteritidis with high specificity. This phage is highly stable under various pH (5-11), temperature ($4-60^{\circ}C$), and organic solvent conditions. The KFS-SE1 genome consisted of 59,715 bp with 73 predicted open reading frames and 57.14% GC content; it had a complete set of genes required for phage reconstruction. Comparative phylogenetic analysis of KFS-SE1 revealed that it was very similar to the other Salmonella phages in the Siphoviridae family. These characteristics suggest that KFS-SE1 with its high specificity and host lysis activity toward S. Enteritidis may have various potential applications.

• The Plant Pathology Journal
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• v.33 no.1
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• pp.34-42
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• 2017

Grapevine rupestris stem pitting-associated virus (GRSPaV) is a worldwide-distributed pathogen in grapevines with a high genetic variability. Our study revealed differences in the complexity of GRSPaV population in a single host. A single-variant GRSPaV infection was detected from the SK30 grapevine plant. On the contrary, SK704 grapevine was infected by three different GRSPaV variants. Variant-specific RT-PCR detection protocols have been developed in this work to study distribution of the three different variants in the same plant during the season. This study showed their randomized distribution in the infected SK704 grapevine plant. Comparative analysis of full-length genome sequences of four Slovak GRSPaV isolates determined in this work and 14 database sequences showed that population of the virus cluster into four major phylogenetic lineages. Moreover, our analyses suggest that genetic recombination along with point mutations could play a significant role in shaping evolutionary history of GRSPaV and contributed to its extant genetic diversification.

• Journal of Microbiology and Biotechnology
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• v.20 no.1
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• pp.30-38
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• 2010

The contribution of a type II restriction-modification system (R-M system) to genome integrity and cell viability was investigated. We established experimental conditions that enabled the achievement of hemimethylated and unmethylated states for the specific bases of the recognition sequences of the host's DNA. To achieve this, we constructed the MboII R-M system containing only one (i.e., M2.MboII) out of two functional MboII methyltransferases found in Moraxella bovis. Using the incomplete R-M system, we were able to perturb the balance between methylation and restriction in an inducible manner. We demonstrate that upon the SOS-induced DNA repair in mitomycin C treated cells, restriction significantly reduces cell viability. Similar results for the well-studied wild-type EcoRI R-M system, expressed constitutively in Escherichia coli, were obtained. Our data provide further insights into the benefits and disadvantages of maintaining of a type II R-M system, highlighting its impact on host cell fitness.

• Journal of Gastric Cancer
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• v.16 no.1
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• pp.1-7
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• 2016

Epstein-Barr virus-associated gastric carcinoma (EBVaGC) is one of the four subtypes of gastric carcinoma (GC), as defined by the novel classification recently proposed by The Cancer Genome Atlas. EBVaGC has several clinicopathological features such as longer survival and higher frequency of lymphoepithelioma-like carcinoma (LELC) and carcinoma with Crohn's disease-like lymphoid reaction that distinguish it from EBV-negative GC. The intensity and pattern of host cellular immune response in GC have been found to significantly correlate with the prognosis of patients with GC, suggesting that immune reaction and tumor microenvironment have critical roles in the progression of GC, and in particular, EBVaGC. Here, we reviewed the cellular and molecular mechanisms underlying prominent immune reactions in patients with EBVaGC. In EBVaGC, deregulation of the expression of immune response-related genes promotes marked intra-or peritumoral immune cell infiltration. The expression of programmed death receptor-ligand 1 is known to be increased in EBVaGC, and therefore, it has been proposed as a favorable prognostic factor for patients with EBVaGC, albeit some data supporting this claim are controversial. Overall, the underlying mechanisms and clinical significance of the host cellular immune response in patients with EBVaGC have not been thoroughly elucidated. Therefore, further research is necessary to better understand the role of tumor microenvironment in EBVaGC.

• The Plant Pathology Journal
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• v.37 no.1
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• pp.1-23
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• 2021

Resistance to diseases caused by turnip mosaic virus (TuMV) in crop species of the family Brassicaceae has been studied extensively, especially in members of the genus Brassica. The variation in response observed on resistant and susceptible plants inoculated with different isolates of TuMV is due to a combination of the variation in the plant resistome and the variation in the virus genome. Here, we review the breadth of this variation, both at the level of variation in TuMV sequences, with one eye towards the phylogeny and evolution of the virus, and another eye towards the nature of the various responses observed in susceptible vs. different types of resistance responses. The analyses of the viral genomes allowed comparisons of pathotyped viruses on particular indicator hosts to produce clusters of host types, while the inclusion of phylogeny data and geographic location allowed the formation of the host/geographic cluster groups, the derivation of both of which are presented here. Various studies on resistance determination in particular brassica crops sometimes led to further genetic studies, in many cases to include the mapping of genes, and in some cases to the actual identification of the genes. In addition to summarizing the results from such studies done in brassica crops, as well as in radish and Arabidopsis (the latter as a potential source of candidate genes for brassica and radish), we also summarize work done using nonconventional approaches to obtaining resistance to TuMV.

• Biomolecules & Therapeutics
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• v.30 no.1
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• pp.64-71
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• 2022

Norovirus (NV) is the most common cause of viral gastroenteritis, with the potential to develop into a fatal disease in those who are immuno-compromised, and effective vaccines and treatments are still non-existent. In this study, we aimed to elucidate the molecular mechanism of the previously identified NV replication inhibitor utilizing a vinyl-stilbene backbone, AC-1858. First, we confirmed the inhibition of the NV RNA replication by a structural analog of AC-1858, AC-2288 with its exclusive cytoplasmic sub-cellular localization. We further validated the induction of one specific host factor, the phosphorylated form of heat shock factor (HSF)-1, and its increased nuclear localization by AC-1858 treatment. Finally, we verified the positive and negative impact of the siRNA-mediated downregulation and lentivirus-mediated overexpression of HSF-1 on NV RNA replication. In conclusion, these data suggest the restrictive role of the host factor HSF-1 in overall viral RNA genome replication during the NV life cycle.

• Korean Journal of Microbiology
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• v.51 no.3
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• pp.194-198
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• 2015

Enterococcus faecalis is a Gram-positive and facultative anaerobic bacterium that causes many hospital-acquired infections. Novel E. faecalis specific bacteriophage (phage) ECP3 that had been isolated from thirty-four environmental samples and characterized phenotypically and genotypically. ECP3 phage belongs to the family Myoviridae with contractile tail and lysed E. faecalis specifically but other bacteria including Enterococcus faecium. The genome was double-stranded linear DNA and its size was 145,518 bp comprising of 220 open reading frames. The GC content was 35.9%. The genome sequence showed 97% identity in 90% coverage region with Myoviridae phage PhiEF24C. ECP3 is the first E. faecalis-specific Myoviridae phage isolated in Korea which can be a promising antimicrobial agent against E. faecalis infections.