• Title/Summary/Keyword: Infectivity

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Petunia Asteroid Mosaic Virus Isolated from Petunia hybrida Vilm. (폐츄니아에서 분리한 Petunia Asteroid Mosaic Virus)

  • 노궤미;최충원;최장경
    • Korean Journal Plant Pathology
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    • v.11 no.4
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    • pp.361-366
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    • 1995
  • A virus was isolated from petunia (Petunia hybrida Vilm.) plants showing chlorotic ring spots on the leaves and color breaking on the flowers, and was identified as petunia asteroid mosaic virus (PAMV). Identification of the PAMV was established by host range test, electron microscopy, serological reaction, and physical properties of the virus. In the host range test, Nicotiana glutinosa, N. rustica, N. clevelandii, P. hybrida, Gomphrena globosa, and Chenopodium amaranticolor were systemically infected with the virus. The virus produced local lesions on inoculated leaves of N. tabacum‘Samsun’, N. tabacum‘Xanthi nc’, Datura stramonium, Vigna unguiculata‘White eye’, C. quinoa, Capsicum annuum, Vicia faba, and Lycopersicon esculentum‘Rutgers’. However, Cucurbita sativus and C. moschata did not show any symptoms. PAMV particles were isometric with 30 nm in diameter. The crude sap from G. globosa infected with the virus reacted positively with antiserum to tomato bushy stunt virus (TBSV) in agar gel double diffusion test. Thermal inactivation point of the virus was 8$0^{\circ}C$ and the virus retained its infectivity at the dilution of 10-4. Longevity in vitro of the virus was estimated longer than 35 days.

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Use of Triton X-100 and Sephacryl S-500 HR for the Purification of Cymbidium Mosaic Virus from Orchid Plants

  • Han, Jung-Heon;La, Yong-Joon;Lee, Cheol-Ho
    • The Plant Pathology Journal
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    • v.15 no.1
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    • pp.34-37
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    • 1999
  • Cymbidium mosaic virus (CyMV) was purified from CyMV infected orchid plant leaves by Sephacryl S-500 HR column chromatography. Partial purification was done by solubilization with Triton X-100 (alkylphenoxypolyethoxy ethanol) and precipitation with polyethylene glycol (PEG 6,000) followed by ultracentrifugation on 30% sucrose cushion. Based on the spectrophotometric analysis, 33 mg of CyMV could be obtained form 100 g of CyMV-infected orchid plant leaves. The purified CyMV represented one distinct homogeneous band by SDS-PAGE, and electron microscopy revealed that it was highly homogeneous and not fragmented. Bioassay demonstrated that the purified CyMV had a normal infectivity to Chenopodium amaranticolor and orchid plants. Based on these results, the purification method in this work could be served as an improved method for the purification of CyMV and similar viruses with good yield, high purity and native integrity.

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New trends of vaccine development: Recombinant vaccinia viruses (expression vectors) as vaccines (Vaccine개발(開發)의 새로운 동향(動向) : Vaccinia virus를 발견(發見) vector로 이용하는 재조합(再組合) 생(生)vaccine의 작성(作成))

  • Kim, Uh-ho
    • Korean Journal of Veterinary Research
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    • v.29 no.3
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    • pp.407-416
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    • 1989
  • The prospect of live vaccines consisting of genetically modified vaccinia virus expressing foreign genes is exciting, but important issues concerning safety and efficacy need to resolved. Vaccinia virus (VV) is an efficient expression vector with broad host range infectivity and large DNA capacity. This vector has been particularly useful for identifying target antigens for humoral and cell-mediated immunity. The WHO smallpox eradication program, involving the extensive use of VV vaccines, resulted in the late 1970s in the elimination of one of the world's most feared diseases. This achievement is a triumph for preventive medicine and for international collaboration in public health. In 1980, WHO recommended that the routine use of smallpox vaccine should be stopped. Against this background, the prospect of li ve vaccines consisting of genetically modified VV expressing foreign antigens arising from the work of Moss, and Paoletti and their colleagues in 1982 has been greeted with enthusiasm. These investigators have shown that genes coding for immunogenic proteins can be inserted into VV DNA without impairing the ability of the virus to grow in cell culture. Moreover experimental animals infected with VV recombinants containing genes coding for a variety of immunizing proteins have been shown to be protected against challenge infection with the corresponding infectious agent. In this communication, I describe current progress in the construction of a novel plasmid vector that facilitate the insertion and expression of foreign genes in VV as well as the selection of recombinants.

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Murine susceptibility to Avian pneumovirus (APV) of turkey origin (칠면조에서 분리된 Avian pneumovirus(APV)의 쥐의 감염성에 대한 연구)

  • Shin, Hyun-Jin
    • Korean Journal of Veterinary Research
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    • v.41 no.4
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    • pp.529-533
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    • 2001
  • The infectivity of an isolate of avian pneumovirus (APV) from turkeys to Balb/c mice was investigated to examine the transmission possibility to mammals. Three different age groups (3, 5 and 7 weeks old) were exposed by oculonasal route with a cell cultured APV of turkey origin. No clinical signs were observed from both APV-inoculated and commingled mice. However, all the tissue samples including blood from mice in the APV-inoculated group were positive for APV by polymerase chain reaction (PCR) up to 6 days postinoculation. At 14 days postinoculation, APV was not detected from blood samples by PCR, but sera showed the presence of APV-specific antibodies. In commingled mice, APV was detected from lung and rectal swap samples by PCR. These results suggest that an APV isolate from turkey could be transmitted to mice by direct contact or other ways.

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Agroinfiltration-based Potato Virus X Replicons to Dissect the Requirements of Viral Infection

  • Park, Sang-Ho;Kim, Kook-Hyung
    • The Plant Pathology Journal
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    • v.22 no.4
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    • pp.386-390
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    • 2006
  • Extensive research of the Potato virus X(PVX) has been performed in in vitro transcription system using the bacteriophage T7 promoter. We constructed an efficient T-DNA based binary vector, pSNU1, and modified vectors carrying PVX replicons. The suitability of the construct to transiently express PVX RNA using Agrobacterium tumefaciens was tested by analysis of infectivity in plants. The expressed PVX RNA was infectous and systemically spread in three plant species including Nicotiana benthamiana, N. tabacum cv. Xanthi-nc, and Capsicum annuum cv. Chilsungcho. The PVX full length construct, pSPVXp31, was caused severe mosaic symptoms on N. benthamiana, severe necrotic lesions on C. annuum while milder symptoms and delayed mosaic symptoms were appeared on the systemic leaves on N. tabaccum. RT-PCR analysis confirmed the presence of PVX RNAs on both inoculated and systemic leaves in all three plant species tested. Our results indicated that PVX replicons were efficiently expressed PVX RNA in at least three tested species. Further investigation win be needed to elucidate the mechanism of PVX replication, translation, movement and assembly/disassembly processes.

Cytotoxicity of Cytosine Deaminase (CD) Adenoviral Vectors(AV) with a Promoter (L-plastin) for Epithelial Cancer Cells.

  • Chung, Injae;Jung, Kihwa;Deisseroth, Albert B.
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 1997.04a
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    • pp.80-80
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    • 1997
  • The object of this study was to develop a gene therapy strategy for ovarian cancer. We have previously shown that AV with a L-plastin (LP) promoter infects breast and ovarian cancer cells and expressed ${\beta}$-galactosidase cDNA in preference to normal fibroblast cells and hematopoietic cells. We now report on the cytotoxicity of Ad.LP.CD, an AV carrying a CD cDNA which converts the pro-drug, 5-Fluorocytosine (5-FC) into the toxic drug 5-Fluorouracil (5-FU). Infection of Ad.LP.CD into either 293 cells or ovarian cancer cells generated the functional CD as measured by HPLC analysis. Using a ratio of AV to OVCAR3 cell of 100 and a 5-FC concentration of 100 ${\mu}$M, we achieve an over 95 % of cell growth inhibition. We are using flow cytometry analysis for ${\beta}$ -galactosidase and ovarian cancer associated folate receptor to screen primary ascites samples for infectivity after infection with an adenoviral vector, i.e., Ad.LP.LacZ. This vector system may be of value in the treatment of microscopic disease of ovarian cancer in the peritoneal cavity.

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A Newly Isolated Bacteriophage, PBES 02, Infecting Cronobacter sakazakii

  • Lee, Hyung Ju;Kim, Wan Il;Kwon, Young Chan;Cha, Kyung Eun;Kim, Minjin;Myung, Heejoon
    • Journal of Microbiology and Biotechnology
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    • v.26 no.9
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    • pp.1629-1635
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    • 2016
  • A novel bacteriophage, PBES 02, infecting Cronobacter sakazakii was isolated and characterized. It has a spherical head of 90 nm in diameter and a tail of 130 nm in length, and belongs to Myoviridae as observed under a transmission electron microscope. The major virion protein appears to be 38 kilodaltons (kDa) in size. The latent period of PBES 02 is 30 min and the burst size is 250. Infectivity of the phage remained intact after exposure to temperatures ranging from 4℃ to 55℃ for 1 h. It was also stable after exposure to pHs ranging from 6 to 10 for 1 h. The phage effectively removed contaminating Cronobacter sakazakii from broth infant formula. PBES 02 has a double-stranded DNA genome of 149,732 bases. Its GC ratio is 50.7%. Sequence analysis revealed that PBES 02 has 299 open reading frames (ORFs) and 14 tRNA genes. Thirty-nine ORFs were annotated, including 24 related to replication and regulation functions, 10 related to structural proteins, and 5 related to DNA packaging. The genome of PBES 02 is closely related to that of two other C. sakazakii phages, CR3 and CR8. Comparison of DNA sequences of genes encoding the major capsid protein revealed a wide geographical distribution of related phages over Asia, Europe, and America.

Studies on Infectivity of Cordyceps, Paecillomyces japonica, on the Domestic Silkworm, Bombyx mori. (눈꽃 동충하초균의 누에감염에 관한 연구)

  • Yun, Jae-Su
    • The Korean Journal of Pesticide Science
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    • v.4 no.4
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    • pp.77-80
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    • 2000
  • This study was carried out to investigate infection process, symptoms and $LD_{50}$ values of the entomopathogenic fungus cordyceps, Paecillomyces japonica, on the domestic silkworm, Bombyx mori. Susceptibility of infection in the silkworms by cordyceps, Paecillomyces japonica, was 100% in $10^{7}$ block, 96% in $10^{6}$ block, 76% in $10^{5}$ block, 44% in $10^{4}$ block, 28% in $10^{3}$ block and 8% in $10^{2}$ block. Cordyceps, Paecillomyces japonica, was highly infectious to the silkworms. A pathogenicities of cordyceps, Paecillomyces japonica, may be highly virulent because of the low resistance or high susceptibility of the silkworms. Dosage of the pathogen of $LD_{50}$ was $3.78{\times}10^{3}\;spores/mm^{3}$.

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An Overview of the Genetic Variations of the SARS-CoV-2 Genomes Isolated in Southeast Asian Countries

  • Yap, Polly Soo Xi;Tan, Tse Siang;Chan, Yoke Fun;Tee, Kok Keng;Kamarulzaman, Adeeba;Teh, Cindy Shuan Ju
    • Journal of Microbiology and Biotechnology
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    • v.30 no.7
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    • pp.962-966
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    • 2020
  • Monitoring the mutation dynamics of human severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is critical in understanding its infectivity, virulence and pathogenicity for development of a vaccine. In an "age of mobility," the pandemic highlights the importance and vulnerability of regionalization and labor market interdependence in Southeast Asia. We intend to characterize the genetic variability of viral populations within the region to provide preliminary information for regional surveillance in the future. By analyzing 142 complete genomes from South East Asian (SEA) countries, we identified three central variants distinguished by nucleotide and amino acid changes.

Edwardsiella ictaluri Infection in Cultured Yellow Catfish Pelteobagrus fulvidraco Fingerlings in Korea (양식 동자개(Pelteobagrus fulvidraco)의 Edwardsiella ictaluri 감염)

  • Kim, Jin Do;Park, Sung Woo
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.48 no.5
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    • pp.725-730
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    • 2015
  • We observed yellow catfish Pelteobagrus fulvidraco fingerlings cultured in land ponds in Korea swimming in a corkscrew spiral pattern while hanging head-up and tail-down at the water surface, before eventually dying. Externally, these fish displayed “hole in the head” disease, pale gills, and hemorrhages in the base of the pectoral and caudal fins; internally they had liver hemorrhages and kidney discoloration. The bacterium Edwardsiella ictaluri (YCK-01 and YCL-01) was identified in the kidneys and livers of diseased fish via phenotypic characteristics and PCR analysis using the ictaluri-specific primers IVS (an intervening sequence) and IRS (the inter-ribosomal spacer). Infectivity challenges by intraperitoneal and immersion routes showed that a representative bacterial strain (YCK) exhibited strong virulence to yellow catfish, with an LD50 of 3.2×104 CFU/fish and 2.5×106 CFU/mL, respectively. This is the first report of E. ictaluri infection in yellow catfish from Korea.