• Molecules and Cells
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• v.40 no.5
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• pp.339-345
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• 2017

Retroviral and lentiviral vectors are mostly pseudotyped and often purified and concentrated via ultracentrifugation. In this study, we quantified and compared the stabilities of retroviral [murine leukemia virus (MLV)-based] and lentiviral [human immunodeficiency virus (HIV)-1-based] vectors pseudotyped with relatively mechanically stable envelope proteins, vesicular stomatitis virus glycoproteins (VSVGs), and the influenza virus WSN strain envelope proteins against ultracentrifugation. Lentiviral genomic and functional particles were more stable than the corresponding retroviral particles against ultracentrifugation when pseudotyped with VSVGs. However, both retroviral and lentiviral particles were unstable when pseudotyped with the influenza virus WSN strain envelope proteins. Therefore, the stabilities of pseudotyped retroviral and lentiviral vectors against ultracentrifugation process are a function of not only the type of envelope proteins, but also the type of viral internal core (MLV or HIV-1 core). In addition, the fraction of functional viral particles among genomic viral particles greatly varied at times during packaging, depending on the type of envelope proteins used for pseudotyping and the viral internal core.

• Korean Journal of Microbiology
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• v.31 no.3
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• pp.184-188
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• 1993

Novel Ustilagomaydis strains, designated as SH1 to 14 containing new types of ds RNA segments, are identified from corn smut in Korea. Among 14 isolates, 7 isolates appear to posses virus particles and the other isolates may contain dsRNA as a plasmid form. The pattern of dsRNA is highly diverse form a typical P-type containing one or more of H, M, and L dsRNAs to the one containing one or move M dsRNAs. It is likely that the strains containing H dsRNA posses virus particles which were confirmed by sucrose density gradient followed with different range of specificity and the activity of the strain (SH14) is stronger than A4 toxin. The sensitivity of 14 isolates is also very diverse and two strains (SH10, SH11) appear tobe universal sensitve strains against 5 tested toxin samples.

• Journal of agriculture & life science
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• v.44 no.6
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• pp.141-146
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• 2010

In this study, Agrobacterium-mediated transformation was tested to the mycelium culture of Flamulina velutipes which is very popular as an edible mushroom in Korea. Particularly, aluminum oxide particles were used to generate wounds in F. velutipes mycelia via vigorous shaking prior to agro-infiltration. The result showed that transformants resistant to hygromycin could be obtained only from the mycelia with physical wounds. Gene transfer was verified by genomic DNA PCR. This study suggested a convenient tool to improve Agrobacterium-mediated transformation of F. velutipes.

• Food Science of Animal Resources
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• v.40 no.5
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• pp.746-757
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• 2020

Enterotoxigenic Escherichia coli (ETEC) is the major pathogenic E. coli that causes diarrhea and edema in post-weaning piglets. In this study, we describe the morphology and characteristics of ØCJ19, a bacteriophage that infects ETEC, and performed genetic analysis. Phage ØCJ19 belongs to the family Myoviridae. One-step growth curve showed a latent phase of 5 min and burst size of approximately 20 phage particles/infected cell. Phage infectivity was stable for 2 h between 4℃ and 55℃, and the phage was stable between pH 3 and 11. Genetic analysis revealed that phage ØCJ19 has a total of 49,567 bases and 79 open reading frames (ORFs). The full genomic sequence of phage ØCJ19 showed the most similarity to an Escherichia phage, vB_EcoS_ESCO41. There were no genes encoding lysogeny, toxins, virulence factors, or antibiotic resistance in this phage, suggesting that this phage can be used safely as a biological agent to control ETEC. Comparative genomic analysis in terms of the tail fiber proteins could provide genetic insight into host recognition and the relationship with other coliphages. These results showed the possibility to improve food safety by applying phage ØCJ19 to foods of animal origin contaminated with ETEC and suggests that it could be the basis for establishing a safety management system in the animal husbandry.

• Journal of Applied Biological Chemistry
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• v.58 no.3
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• pp.273-279
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• 2015

Phaeodactylum tricornutum is a model diatom that its genomic information and biological tools are well established. In this study, a gene encoding (E)-4-hydroxy-3-methylbut-2-enyl diphosphate reductase (PtHDR), a terminal enzyme of the methylerythritol phosphate pathway regulating chlorophyll and carotenoid biosynthesis, was isolated from P. tricornutum. The isolated gene was cloned into pPha-T1 vector containing fcpA promoter to prepare pPha-T1-HDR plasmid. As a positive control, pPha-T1-eGFP plasmid was constructed with egfp gene. Stable nuclear transformation was carried out with these plasmids by particle bombardment method and zeocin resistant colonies of P. tricornutum were selected on f/2 agar plate. In result, transformation efficiency was evaluated according to the amount of plasmid DNA coated with gold particles. Integration of introduced plasmids was confirmed with genomic DNA of each transformant by polymerase chain reaction. The eGFP fluorescence was visible in the cytoplasm, indicating that eGFP was successively expressed in P. tricornutum system. The transcript level of exogenous Pthdr gene was evaluated with the obtained transformants. The results presented here demonstrated that introduction of Pthdr gene into P. tricornutum chromosome succeeded and expression of PtHDR was enhanced under the fcpA promoter.

• The Plant Pathology Journal
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• v.21 no.2
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• pp.167-171
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• 2005

We isolated the Cucumber green mottle mosaic virus(CGMMV) particles from watermelon leaves and designated as CGMMV-HY1 as a watermelon isolate and attempted to characterize the pathogenic isolate responsible for such an epidemic in watermelon and also to monitor dominant viral isolates in greenhouse. The watermelon plants infected with CGMMV generally showed mottle mosaic, mosaic, growth stunting, necrosis and deformed fruit. The reactions of indicator plants to CGMMV-HY1 were the local lesions on Nicotiana tabacum cv. White Burley, Nicotiana tabacum cv. Samsun, and Chenopodium amaranticola, and the mosaic symptoms only on Cucumis sativus, but the CGMMV-HY1 did not infect Nicotiana sylvesytis, Datura stramonium, Chenopodium quinoa, and Petunia hybrida. Purified virus particles were rod-shaped and about 300 nm long. The coat protein (CP) of purified CGMMV-HY1 was single band with molecular weight of about 16.5 kDa which was confirmed by western blot analysis probed with monoclonal antibody of CGMMV-HY1. The genomic and subgenomic RNAs of 6.4 kb and 0.75 kb were revealed by the electrophoresis on 1.2% formaldehydedenatured agarose gel. Viral and complementary CGMMV-specific primer sets were designed for spanning the genome using previously reported CGMMV sequences. A 464bp of CP gene of CGMMV-HY1 was amplified by RT-PCR and cloned into PGEM-T easy vector. The nucleotide sequence of CP gene of CGMMV-HY1 shared 98%, 99%, and 100% identities with that of CGMMV strains W, KOM, and KW respectively. Based on these results, we identified CGMMV-HY1 as a CGMMV isolate of watermelon, a member of Tobamovirus.

• Korean Journal of Veterinary Research
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• v.32 no.1
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• pp.77-82
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• 1992

A noncytopathic bovine viral diarrhea virus(NC BVDV) strain isolated and purified from persistently infected primary bovine fetal lung(BFL) cells was studied by biophysical methods. The buoyant density of particles of the NC BVDV strain was shown to be between 1,090 and $1,114g/cm^3$ and the maximum virus infectivity occured at $1,098g/cm^3$. Immunoelectron microscopic examination by using the partially purified virus revealed regular spherical particles 30~80nm in diameter. Differences in the genomic size of cytopathic and noncytopathic BVDV from infected cells were not found. A comparison of viral proteins of a noncytopathic and cytopathic strain(NADL) by immunoprecipitation using monoclonal antibody indicated that NC BVDV, compared to cytopathic NADL, was cell associated.

• The Plant Pathology Journal
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• v.20 no.4
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• pp.297-301
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• 2004

A Tomato spotted wilt virus (TSWV-KP) was isolated from Paprika (Capsicum annuum var. grossum) showing necrosis spot on the leaves and malformation of the fruit in Yesan, Korea. The virus infected Chenopodium amaranticolor, C. quinoa, Petunia hybrida, Nicotiana glutunosa, Gomphrena globosa, and Physalis floridana. Ten plants including tomato were observed to have systemic TWSV-KP infection. The virus produced necrosis or necrotic ring spots on the inoculated leaves and mosaic, vein necrosis or death on the upper leaves of Datura stramonium, N. clevarandii, N. rustica, and N.tabacum cvs. Thin sections of the infected leaf tissue contained spherical to oval particles, a characteristic of a Tospovirus. The virion contained three molecules of genomic RNAs, which were approximately 9.0, 4.9 and 3.0 kb. The nucleocapsid (N) protein of the purified virion migrated as a single band with molecular weight of about 29 kDa in SDS-PAGE. The N gene of TSWV-KP showed 96.5-97.2% and 97.7-98.5% identities to the three different TSWV isolates of Genbank Database at the nucleotide and amino acid, respectively.

• Journal of Applied Biological Chemistry
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• v.42 no.3
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• pp.113-118
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• 1999

The transgenic plant of Citrus species (Citrus aurantium L.) was constructed with a fatty acid desaturase gene using microprojectile bombardment transformation system. The DNA of a fatty acid desaturase gene, fad7, constructed in pBI121 was coated onto tungsten particles ($1.1{\mu}m$) and introduced into callus cells by bombarding with 1100 psi of helium pressure, 1/4 in of gap distance, 7.0 cm of target distance and 27 in Hg of chamber vacuum. The bombarded cells were selected on the medium containing kanamycin. The selected cells were successfully regenerated into plantlets via somatic embryogenesis on the media containing plant growth regulators. The results of polymerase chain reaction analysis of genomic DNAs from the putative transformants showed that the introduced DNAs of fad7 were present in both the selected callus cells and the regenerated plantlets.

• BMB Reports
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• v.48 no.12
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• pp.685-690
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• 2015

The eukaryotic genome is packed into chromatin, which is important for the genomic integrity and gene regulation. Chromatin structures are maintained through assembly and disassembly of nucleosomes catalyzed by histone chaperones. Asf1 (anti-silencing function 1) is a highly conserved histone chaperone that mediates histone transfer on/off DNA and promotes histone H3 lysine 56 acetylation at globular core domain of histone H3. To elucidate the role of Asf1 in the modulation of chromatin structure, we screened and identified small molecules that inhibit Asf1 and H3K56 acetylation without affecting other histone modifications. These pyrimidine-2,4,6-trione derivative molecules inhibited the nucleosome assembly mediated by Asf1 in vitro, and reduced the H3K56 acetylation in HeLa cells. Furthermore, production of HSV viral particles was reduced by these compounds. As Asf1 is implicated in genome integrity, cell proliferation, and cancer, current Asf1 inhibitor molecules may offer an opportunity for the therapeutic development for treatment of diseases.