• Archives of Pharmacal Research
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• v.24 no.1
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• pp.74-78
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• 2001

A preparation of water soluble components (EA) was made from carpophores of Elfvingia applanata (Pers.) Karst and its in vitro antiviral activity on vesicular stomatitis virus [(Indiana serotype, VSV(IND)] was investigated by plaque reduction assay. EA exhibited potent antiviral activity on VSV(IND) growth and negligible cytotoxicity on Vero cells, 50% effective concentration ($EC_{50}C$/) of 104$ug\textrm\/ml$ and 50% cytotoxic concentration ($CC_{50}C$) of 3,793$ug\textrm\/ml$, respectively. Selectivity index (Sl $CC_{50}C$/$EC_{50}C$) of EA on Vero cell and VSV(IND) was about 36.5. EA did not display either a direct virucidal effect on V5V(IND) or induction of antiviral substance by Vero cells upon its treatment. Thus, the mode of antiviral activity of EA was studied at steps of viral adsorption onto cell. When both EA and virus were added to cell monolayers, titer of cell-free virus in culture supernatant increased in ca. 30-40% compared with that of control group and titer of cell-associated virus was 60-100% higher than that of control group. These results suggested that antiviral activity of EA on VSV(IND) might be due to the hindrance of viral entry to cells at eITher endocytosis or loss of envelope.

• Korean Journal of Poultry Science
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• v.46 no.4
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• pp.271-277
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• 2019

In recent years, consumers have recognized the issue of and expressed concern over farm animal welfare. Therefore, worldwide, chicken farms are transitioning from traditional caged breeding systems to welfare-oriented breeding systems. In this study, we further analyzed and compared the prevalence and protection rate of various diseases by challenging chickens under conventional and welfare-oriented breeding conditions with low pathogenic avian influenza. Ten chickens were randomly selected from each farm (conventional and welfare) from which Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS) were identified and isolated. Additionally, low pathogenic avian influenza (LPAI) were challenged to broilers from each farm and samples were collected from these chickens using oral and cloacal swabs to investigate viral shedding and titer. The results showed that Mycoplasma infection did not significantly differ between breeding systems. Initially, LPAI viral shedding and titer significantly differed between breeding systems post-challenge, but as the experiment progressed, there was ultimately no significant difference.

• Journal of Sericultural and Entomological Science
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• v.41 no.2
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• pp.102-107
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• 1999

To analysis a promoter strength of Atographa californica nucler polyhedrosis virus (AcNPV) IE1 gene, an immediate viral gene, ${\beta}$-glactosidase gene as a reporter gene was introduced under the control of the IE1 promoter. The restriction fragment containing IE1 promoter and ${\beta}$-galctosidase gene from pAcIE1-gal were inserter into pBacPAK9 to yield transfer vector pAcNPV-IE1-gal. The pAcNPV-IE1-gal was cotransfected with AcNPV genomic DNA BacPAK6 into Sf9 cells to produce recombinant baculovirus AcNPV-IE1-gal. In addition, recombinant bacvulovirus AcNPV-gal, which express ${\beta}$-galac-tosidase under the control of the polyhedrin promoter, was constrer, was constructed to compared with AcNPV-IE1-gal. The recombinant viruses were respectively infected into Sf9 cells and characterized by the virus titer and expression of ${\beta}$-galactoxidase in Sf9 cells. The promoter strength of IE1 and polyhedrin promoters was determined by the amount of ${\beta}$-galactosidase secreted into medium by viral infection. The titer of AcNPV-IE1-Gal determined by plaque assays in Sf9 cells was similar to that of AcNPV-gal. However, expression level of ${\beta}$-galactosidase by AcNPV-IE1-gal was significantly lower than that by AcNPV-gal. In conclusion, promoter strength of IE1 was approximately 25-fold lower than that of polyhedrin.

• Korean Journal of Veterinary Research
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• v.40 no.1
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• pp.101-109
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• 2000

Duck viral hepatitis is an acute, highly infectious viral disease of young dacklings aged from two days to three weeks. The significant lesion associated with the disease was enlarged liver including necrotic foci and numerous hemorrhagic spots. We have isolated five strains of duck hepatitis virus (DHV) from field cases showing about 20% mortality with a sign of opisthotonos. When a-day-old ducklings were intramuscularly inoculated with one of the isolates, 92% of the birds were died within 5 days. We attempted to develop an attenuated strain of duck hepatitis virus (DHV) using one of the isolates by serial chicken embryo passages. The propagation of DHV in chicken embryos was carried 140 passages. The virus titer increased gradually from the $21^{st}$ through the $50^{th}$ passage, but there was no significant increase of virus titer in subsequent passages after then. Through the serial passages, the virulence of the virus for chicken embryos was gradually increased but decreased for ducklings. The pathogenicity of the virus for ducklings was preserved up to the $21^{st}$ passage but disappeared at the $50^{th}$passage. An attenuated Korean isolate which was passaged 140 times in chicken embryos gave good protection in ducklings against both challenge infection to a Korean virulent strain and to a DHV-DRL strain, a type 1 reference strain of DHV, which indicated that the Korean isolates could be classified as DHV type 1. And the above results suggest that an attenuated Korean isolate can be used for developing a live DHV vaccine.

• Korean Journal of Veterinary Research
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• v.60 no.4
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• pp.195-202
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• 2020

Feline calicivirus (FCV) infection results in a common upper respiratory disease associated with oral ulceration in cats. Although FCV infection has been reported in cats worldwide, the biologic and genetic features of South Korean FCV are unclear. We aimed to investigate the biological and genetic features of South Korean FCV isolates. Crandell-Rees feline kidney (CRFK) cells were used to isolate FCV from 58 organ homogenate samples. The FCV isolates were confirmed by cytopathic effects, immunofluorescence, electron microscopy, and reverse transcription polymerase chain reaction assays. Viral genetic analysis was carried out with VP2 gene and complete genomes of FCVs. Five viruses propagated in CRFK cells were confirmed to be FCVs. The FCV17D283 isolate showed the highest viral titer of 107.2 TCID50/mL at 36 h post-inoculation. Korean FCV isolates did not grow well in Vero, BHK-21, A72, or Madin-Darby canine kidney cells. The FCV17D03 and FCV17D283 isolates had the highest genetic similarity (80.1% and 86.9%) with the UTCVM-H1 and 14Q315 strains, which were isolated in the United States and South Korea in 1995 and 2014, respectively. We isolated five FCVs from cats and detected important genetic differences among them. FCV isolates did not show any virulent effects in mice.

• Journal of Microbiology and Biotechnology
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• v.9 no.4
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• pp.386-392
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• 1999

A large-scale culture of hepatitis A virus in human diploid MRC-5 cells was conducted. In a roller bottle culture, the virus was grown to a maximum titer in 3 weeks after infection. Over 95％ of the cell-associated virus was excreted after culturing the infected cells in suspension media without fetal bovine serum for 3 days. The cultured virus was inactivated with formalin, concentrated by ultrafiltration, and partially purified by ultracentrifugation in a non-ionic gradient medium of Renocal. Two separate peak fractions showing high anti-HAY ELISA titer were pooled and about 40％ of HAV antigen was recovered by this purification procedure. Of the partially purified vaccine, the protein pattern in SDS-PAGE and immunogenicity in mice were compared with a commercial HAV vaccine. In SDS-PAGE, the purified vaccine in this study and the commercial vaccine showed almost the same protein pattern. The seroconversion rate of the purified vaccine in mice was not different from that of the commercial vaccine. Therefore, we could prepare a good grade of HAV vaccine by a simple purification procedure although the purification itself was not completed.

• Fisheries and Aquatic Sciences
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• v.25 no.6
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• pp.320-326
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• 2022

Most of the emerging diseases that threaten humans are caused by RNA viruses which are extremely mutable during evolution. The fish RNA virus, viral hemorrhagic septicemia virus (VHSV) can infect a broad range of aquatic animal hosts, but the transmissibility of VHSV to mammals has not been thoroughly investigated. Therefore, our study aimed to investigate the potential adverse effects of VHSV in mammals. Briefly, the survival of VHSV was determined using only minimum essential media (MEM-2) and mammalian SNU-1411 and hepa-1c1c7s cells at 15℃ and 37℃. Mice (Mus musculus, 27.3 ± 1.9 g) were intravenously injected with VHSV (2.37E+05 TCID₅₀·mice^-1) in triplicate. Clinical signs and survival rates were examined at 14 days post-challenge, and infection was confirmed in the surviving mice. The 50% tissue culture infective dose (TCID₅₀) and polymerase chain reaction analysis were used to determine viral titers and the infection rate, respectively. The titer of VHSV suspended in MEM-2 at 15℃ was reduced by only one log after 8 days, whereas the virus maintained at 37℃ was inactivated 8 days post-inoculation (dpi). There were no recognizable cytopathic effects in either SNU-1411 or hepa-1c1c7s cells inoculated with VHSV at 15℃ and 37℃. VHSV in those cell lines at 37℃ was rapidly decreased and eventually inactivated at 12 dpi, whereas virus at 15℃ remained at low concentrations without replication. In vivo experiment showed that there were no signs of disease, mortality, or infection in VHSV-infected mice. The results of this study indicate that it is highly unlikely that VHSV can infect mammals including humans.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.203-206
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• 2005

TGE (Transmissible Gastroenteritis) caused by a virus belonging to family coronavirus, results in an acute infection of the small intestine of the pig. The optimum operation variables such as multiplicity of infection (MOI), infection time and harvest time were investigated for TGE vaccine production by immobilized ST(swine testicle) cells. In the culture supplemented with 5% serum, maximum virus titer of $1.2{\times}10^6pfu/ml$ was obtained at the conditions of 0.01 MOI, 2day infection time, and 1 day harvest time. Serum is a potential source of bacterial, mycoplasmal and viral contamination, and it has a possibility of the introduction of serum proteins, prion and pyrogens into the final product. For these reasons, much attention has been focused on the development of serum-free media. A new serum-free media (SFM) has been developed in order to produce TGE vaccine of high quality with low cost. The performance of SFM developed was compared with other commercially available serum-free media and serum supplemented media in terms of virus productivity. The cultures with serum-free media showed higher titer than that with serum supplemented media. Among various serum-free media tested, CHO-S-SFMII showed highest virus titer.

• Korean Journal of Veterinary Research
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• v.29 no.2
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• pp.83-90
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• 1989

The changes in serum total protein and immunoglobulin levels, and BVD, IBR and PI-3 viral neutralizing antibody titers in colostrum-conferred Korean native calves during the first 12 weeks postpartum were studied, and the results obtained were summerized as follows: The Mean concentration of total protein, total immunoglobulin, IgG, IgM and IgA in sera of 9 calves at birth were $3.8{\pm}0.5g/dl$, $0.27{\pm}0.15mg/ml$, $0.06{\pm}0.08mg/ml$, $0.21{\pm}0.11mg/ml$, and extremely low concentration, respectively. Serum total protein level reached a maximum at 20 hours after birth, total immunoglobulin, IgG, and IgM levels at 24 hours, and IgA level at 28 hours, respectively. Serum IgA level reached a minimum at 4 weeks old, IgM level at 5 weeks, total immunoglobulin level at 8 weeks, and IgG level at 10 weeks, respectively. After then those levels had begun to increase, but total protein level was still decreasing at 12 weeks old. The half-lives of IgG, IgM, and IgA were 21.1 days, 4.0 days, and 2.6 days-respectively. In 10 Korean native cows immediately after parturition, serum neutralizing antibody titers specific to BVD, IBR and PI-3 virus were $8.7{\pm}1.5{\log}_2$, $5.7{\pm}1.2{\log}_2$, and $6.8{\pm}1.01{\log}_2$, respectively. And colostral neutralizing antibody titers against BVD, IBR, and PI-3 virus were $10.1{\pm}1.4{\log}_2$, $6.8{\pm}1.3{\log}_2$ and $7.8{\pm}1.7{\log}_2$, respectively. Before suckling the colostrum, SN antibody titers against BVD, IBR, and PI-3 virus were undetectable from all of 9 Korean native calves. Nevertheless SN antibody titer against BVD virus reached a maximum level ($9.2{\pm}0.6{\log}_2$) at 24 hours after birth, that against IBR virus ($6.1{\pm}1.0{\log}_2$) at 20 hours after birth, and that against PI-3 virus ($6.8{\pm}0.9{\log}_2$) at 32 hours after birth, respectively. In 12 weeks old calves, the SN antibodies against BVD and IBR virus were still decreasing, but that against PI-3 virus reached a minimum at 10 weeks, and increased after 12 weeks of age. The half-lives of SN antibodies against BVD, PI-3 and IBR, virus were 16.0 days, 22.6 days, and 25.5 days, respectively.

• Journal of fish pathology
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• v.24 no.2
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• pp.47-51
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• 2011

The present study demonstrated lymphocystis disease virus (LCDV) propagation through cytopathic effects (CPE) formation and LCDV detection in olive flounder fin (FFN) cells by polymerase chain reaction (PCR) and fluorescent antibody technique (FAT) methods. Tissue filtrates from the cluster cells produced CPE in FFN cells, which initially cells became enlarged and gradually underwent fusion en masse. Infectivity of culture grown LCDV using the FFN cells reached $10^{2.3}$ $TCID_{50}$/ml at 4 days post infection and the highest titer was measured $10^{6.5}$ $TCID_{50}$/ml at 12 days. The viral DNA was detected in the cell culture supernatants showing CPE and the CPE cells by PCR. Antigen specific strong fluorescence reacting with monoclonal antibody against the virus revealed the presence of viral antigen in the cytoplasm of infected FFN cells. These results suggest that the FFN cell line originated from the olive flounder has a susceptibility of the LCDV.