• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.65.1-65
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• 2003

In addition to the five well-characterized genes of Tobacco mosaic virus (TMV), this virus contains a sixth open reading frame (ORF6) that encodes a 4.8 kDa protein. TMV ORF6 overlaps the ORFs encoding the 30 kDa movement protein and the adjacent 17.5 kDa capsid protein. Although the 4.8 kDa protein could not be detected in vivo, alteration of the AUG codons of this ORF resulted in a mutant virus that attenuated the virulence of the mutated TMV in Nicotiana benthamiana, but not N. tabacum (tobacco). These sequence changes did not affect either the replication or movement of the mutated TMV. Expression of TMV ORF6 from the virus expression vector Potato virus X (PVX) intensified the virulence of this virus in N. benthmiana, but not tobacco, while expression of TMV ORF6 from the virus expression vector Tobacco rattle virus enhanced the pathogenicity observed in both N. benthamima and tobacco. Thus, the TMV ORF6 is a host- and virus-specific. virulence factor. However, two separate assays indicated that the TMV 4.8 kDa protein was not a suppression of RNA silencing. A fusion protein formed between the TMV 4.8 kDa protein and the green fluorescent protein was expressed from the PVX vector and localized to plasmodesmata. Possible roles of the 4.8 kDa protein in pathogenicity will be discussed

• Journal of Veterinary Science
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• v.22 no.4
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• pp.42.1-42.16
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• 2021

Background: Inclusion body hepatitis (IBH) is an economically important viral disease primarily affecting broiler and breeder chickens. All 12 serotypes of fowl adenovirus (FAdV) can cause IBH. Objectives: To characterize FAdV isolates based on phylogenetic analysis, and to study the pathogenicity of FAdV-8b in specific-pathogen-free (SPF) chickens following virus inoculation via oral and intramuscular (IM) routes. Methods: Suspected organ samples were subjected to virus isolation and polymerase chain reaction (PCR) for FAdV detection. Hexon gene sequencing and phylogenetic analysis were performed on FAdV-positive samples for serotype identification. One FAdV-8b isolate, UPM/FAdV/420/2017, was selected for fiber gene characterization and pathogenicity study and was inoculated in SPF chickens via oral and IM routes. Results: The hexon gene phylogenetic analysis revealed that all isolates belonged to FAdV-8b. The fiber gene-based phylogenetic analysis of isolate UPM/FAdV/420/2017 supported the grouping of that isolate into FAdV species E. Pathogenicity study revealed that, chickens infected with UPM/FAdV/420/2017 via the IM route had higher clinical score values, higher percent mortality, higher degree of the liver lesions, higher antibody response (p < 0.05), and higher virus shedding amounts (p < 0.05) than those infected via the oral route. The highest virus copy numbers were detected in liver and gizzard. Conclusions: FAdV-8b is the dominant FAdV serotype in Malaysia, and pathogenicity study of the FAdV-8b isolate UPM/FAdV/420/2017 indicated its ability to induce IBH in young SPF chickens when infected via oral or IM routes.

• Journal of Sericultural and Entomological Science
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• v.17 no.2
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• pp.101-118
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• 1975

The pathogenicity of hexagonal and tetragonal cytoplasmic polyhedron virus to one of present leading silkworm varieties, Jam 103${\times}$Jam 104, and its parents, Jam 103 and Jam 104, was investigated. The activation of occult virus by oral inoculation of foreign virus as well as the interference phenomena between the activated and inoculated cytoplasmic polyhedron viruses was observed and the results obtained are as follows. 1. The pathogenicity of cytoplasmic polyhedrosis viruses. 1) There was a high significant difference in the pathogenicity of hexagonal polyhedron virus between the hybrid and its parents showing the lowest infection rate in the hybrid (Jam 103${\times}$Jam 104), medium infection rate in the Japanese line (Jam 103) and the highest infection rate in the Chinese line (Jam 104). In the pathogenicityof tetragonal polyhedron virus, a significant difference was observed only between the hybrid (Jam 103${\times}$Jam 104) and the Chinese line (Jam 104) by showing a higher infection rate in the Chinese line than in the hybrid. 2) The pathogenicity of both hexagonal and tetragonal polyhedron viruses showed a high significant difference in different silkworm instars inoculated by showing a higher infection rate at the second instar than at the fourth instar. 3) The pathogenicity of both hexagonal and tetragonal polyhedron viruses was increased as the concentration of viruses inoculated increased. 2. The phenomena of induction and interference by oral inoculation of foreign virus. 1) The induction rate of cytoplasmic polyhedrosis virus was higher in the parents than in the hybrid. In the parents. a higher rate in the Chinese line than in the Japanese line was observed. 2) The effect of inoculation at different instars on the induction was studied and the induction rate was higher at the second instar inoculated than at the fourth instar inoculated. 3) The degree of activation of hexagonal polyhedron virus with inoculation of tetragonal polyhedron virus was very high when a lower concentration of virus was inoculated and it was very low when a higher concentration of virus was inoculated 4) The degree of activation of tetragonal polyhedron virus with inoculation of hexagonal polyhedron virus was very low when a lower concentration of virus was inoculated and it was not observed when a higher concentration of virus was inoculated. 5) The mixed infection rate with hexagonal and tetragonal polyhedron viruses was higher at the second instar inoculated than at the fourth instar inoculated. 6) It was observed that the secondary hexagonal pc]yhedron virus activated interfered with the primary tetragonal polyhedron virus inoculated when the inoculated concentration of the primary virus is low and the primary virus inoculated interfered with the secondary virus activated when the inoculated concentration of the primary virus is high.

• Journal of fish pathology
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• v.25 no.2
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• pp.117-121
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• 2012

The pathogenicity of viral hemorrhagic septicemia virus (VHSV) from olive flounder Paralichthys olivaceus was investigated with masu salmon Oncorhynchus masou fry. The cumulative mortality of fish challenged with FYeosu05 isolate at $10^{6.5}$ $TCID_{50}$/fish was 60%. No mortality was observed in fish challenged with the isolates at $10^{5.5}$ $TCID_{50}$/fish and in mock-challenged fish. The affected fish showed darkening of the body, expanded abdomen, pale gills and enlarged spleen. VHSV from $10^{6.3}$ to $10^{7.8}$ $TCID_{50}$/g-tissue was re-isolated from the dead fish. These results suggest that the VHSV from olive flounder is pathogenic to masu salmon fry, although with low virulence.

• Korean Journal of Poultry Science
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• v.27 no.2
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• pp.109-114
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• 2000

The objective of these experiments was to develop an attenuated thermostable Newcastle disease virus(NDV), CBP-1 strain isolated from infected pheasants. Safety, pathogenicity and protective effects against velogenic NDV were also investigated to evaluate if the attenuated NDV, CBP-1 strain could be a candidate for a new NDV vaccine strain. CBP-1 strain was passaged up to the 173 times by nine days old embryonated eggs and chicken embryo fibroblast(CEF) cell cultures. Its sensitivitly to lipid solvents and low pH, thermostability, mean death time(MDT), intracerebral pathogenicity index(ICPI) of one day old chicks and intravenous pathogenicity index(IVPI) of four weeks old chicks were examined. Safety, boosting and protective effects were tested by chicks mortality. CBP-1 NDV strain had significant thermostability at 56$\^{C}$ for 30 minutes. by hemagglutinin activity and egg infectivity test, but was not resistant to lipid solvent. It showed possibility to use as a feed or water vaccine because of the resistance to low pH. MDT, ICPI and IVPI of CBP-1 were attenuated from 51.5, 1.96, 2.60 to 112.4, 1.12, 1.45. These results implied that the 173rd passages in embryonated egg and CEF cell cultures induced a substantial attenuation of the pathogenicity of the parent virus, changing the virulence from velogenic to intermediate between mesogenic and lentogenic. After vaccination with CBP-1 at one day old by drinking water mortality was 17.5%. However, spray vaccination with B1 at one day old, CBP-1 at two weeks ild and challenge with velogenic Kyojeongwon strain at four weeks old showed 93.5% survival rate. Mortality of chicks, vaccination with 173rd passaged CBP-1 strain at one day old, two weeks old and challenge with Kyokeongwon strain at four weeks old, was 20.0%. The results of these studies indicated that partial attenuated CBP-1 strain tended to be a low safety for ND of broiler chicks and would need to be more successive attenuation.

• Journal of Microbiology and Biotechnology
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• v.30 no.9
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• pp.1273-1281
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• 2020

Due to the broad host suitability of viral vectors and their high gene delivery capacity, many researchers are focusing on viral vector-mediated gene therapy. Among the retroviruses, foamy viruses have been considered potential gene therapy vectors because of their non-pathogenicity. To date, the prototype foamy virus is the only retrovirus that has a high-resolution structure of intasomes, nucleoprotein complexes formed by integrase, and viral DNA. The integration of viral DNA into the host chromosome is an essential step for viral vector development. This process is mediated by virally encoded integrase, which catalyzes unique chemical reactions. Additionally, recent studies on foamy virus integrase elucidated the catalytic functions of its three distinct domains and their effect on viral pathogenicity. This review focuses on recent advancements in biochemical, structural, and functional studies of foamy virus integrase for gene therapy vector research.

• International Journal of Industrial Entomology and Biomaterials
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• v.1 no.2
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• pp.177-181
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• 2000

Spilarctia obliqua(Wlk.) is a serious pest of mulberry which is naturally affected by its nucleopolyhedrosis virus (SoNPV) in field conditions. The polyhedral occlusion bodies (POB's) were hexahedron under scanning and transmission electron microscope and measured 0.42${\mu}{\textrm}{m}$ to 0.67 ${\mu}{\textrm}{m}$ in diameter. The symptoms of NPV infected S. obliqua larvae resembled with that of other NPVs' infected lepidopterous larvae. The pathogenicity and potentiality of this virus against S. obliqua was tested in the laboratory conditions and the results showed 100% mortality in larvae inoculated with SoNPV at 6.23${\times}10^5$ POBs/ml. Therefore, SoNPV appears to have a high potential as a microbial biocontrol agent against S. obliqua larvae.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.149.1-149
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• 2003

A lily strain of Cucumber mosaic virus (LK-CMV) was not able to systemically infect zucchini squash (Cucurbita pepo), while Fny strain of CMV (Fny-CMV) caused systemic mosaic and stunting symptom at 4 days post-inoculation on the same host species. The pathogenicity of LK-CMV in zucchini squash was investigated by reassortments of genomic RNAs of LK-CMV and Fny-CMV for infection, as well as by pseudorecombinants generated from biologically active transcripts of CDNA clones of LK-CMV and Fny-CMV, respectively. The assessments of pathogenicity for LK-CMV indicated that RNA2 of LK-CMV was responsible for systemic infection in zucchini squash. In the protoplast of zucchini squash, the RNA accumulations of all constructed pseudorecombinants were indistinguishable and LK-CMV replication was slightly lower than that of Fny-CMV, suggesting that the inability of LK-CMV to infect squash plants was responsible for the poor efficiency of virus movement, rather than the reduction of replication function.

• Korean journal of applied entomology
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• v.29 no.3
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• pp.184-189
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• 1990

A nuclear polyhedrosis virus (NPV) of the tobacco cutworm, Spodoptera litura would be a promisible agent for the control of the insect. To develop a viral insecticide using S. litura NPV, effect of spray on soybean leaves, temperature, storage, an sunlight on the pathogenicity of the virus were studies as follows: Median lethal concentration ($LC_{50}$) of the virus sprayed on the leaves against the third and the fifth instar larvae were $1.301\times10^{4 PIBS}/ml$ and $1.087\times10^{5 PIBS}/ml$, respectively. On the concentration of $1.0\times10^{5 PIBS}/ml$, median lethal times ($LT_{50}$) were 7.3 days for the 3rd and 8.9 days for the 5th instar larvae. Stability of S. litura NPV was quickly decreased at the higher temperate than $60^{\circ}C$ and at the longer exposure to the higher temperature. Storage of the virus at $-20^{\circ}C$ was kept higher pathogenicity than $4^{\circ}C$ and $25^{\circ}C$. Viral activity was maintained more than 10 days in the sprayed-under leaves, but decreased at 3 day after spray in th sprayed-on the leaf surface when exposed the virus to sunlight.

• Korean Journal of Veterinary Research
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• v.30 no.1
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• pp.65-71
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• 1990

Rabbits were experimentally infected with rabbit hemorrhagic disease virs and the viral pathogenicity, hemagglutinability, and the effect of physicochemical factors were studied. The experimental results were summariaed as follows: 1. Mean rectal temperature of 11 infected rabbits was $40.0{\pm}0.47^{\circ}C$ prior to the virus inoculation, and $39.9{\pm}0.75^{\circ}C$ after 12hrs., $40.2{\pm}0.65^{\circ}C$ after 24hrs., $40.1{\pm}0.77^{\circ}C$ after 36hurs, and $40.6{\pm}0.56^{\circ}C$ just before the death. 2. Mean death time of infected rabbits was $40.3{\pm}22.0$ honrs and its range was 24 to 93 hours. 3. O, B, AB and A type of human erythrocytes were shown their HA in the order, but rabbit and chicken erythrocytes were not hemagglutinated by the virus. 4. In the hemagglutination, less than 0.25 per cent of a final concentration of erythrocytes and 0.2 per cent of BSA in PBS resulted in the best hemagglutination. Phosphate concentration in a range of 0.01M to 0.10M in PBS was not influenced on the hemagglutination reaction, and its pH 7.0 resulted in a better HA. 5. The hemagglutinating titers, in log 2 scale, of organs and tissues of the virus infected rabbits were $9.3{\pm}3.8$ (liver), $9.1{\pm}3.9$ (blood), $6.2{\pm}2.6$ (spleen) and $5.0{\pm}2.5$ (kidney). 6. The physicochemical factors such as heating ($50^{\circ}C$, 10 min.), trypsin treatment (0.05 pre cent, 5 min.), acid treatment (pH 3.0, 20 min.) and ether extraction (3 times) were not affective to the stability of virus and viral HA activities.