• Journal of Veterinary Clinics
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• v.29 no.1
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• pp.63-67
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• 2012

Mosquitoes are the vectors of a number of viral diseases in cattle, such as Akabane disease, bovine ephemeral fever, Ainovirus infection, Chuzan virus infection, and Ibaraki disease. These diseases are transmitted from an infected animal to a non-infected host via the blood feeding of the vector. In Korea, the National Veterinary Research and Quarantine Services, Ministry for Food, Agriculture, Forestry and Fisheries is responsible for planning, implementation, laboratory investigations and reporting the results of the national surveillance program for mosquito-borne bovine diseases (MBD). The surveillance program, which was started in 1993, focused to determine the seroprevalence of each disease in cattle herds in space and time. From the epidemiological point of view, more important component of the surveillance program is to monitor infection rates in vectors for specific pathogens because this information is essential for a more precise understanding the dynamics of these diseases in a given environment and for determining risk of transmission. The aim of this study was to describe and compare methods for estimation of vector infection rates using maximum likelihood (MLE) and minimum infection rate in pooled samples. Factors affecting MLE such as number of pools, pooling size and diagnostic test performance are also discussed, assuming some hypothetical sampling scenarios for MBD.

• Biomolecules & Therapeutics
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• v.17 no.2
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• pp.138-143
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• 2009

We have reported previously on a replication incompetent recombinant adenoviral vector, AdLPCD, in which the expression of cytosine deaminase gene (CD) is driven by the tumor-specific L-plastin promoter. AdLPCD vector had been evaluated for its efficacy of chemosensitization of ovarian cancer cells to 5-FC. In spite of the fact that ovarian cancer cells, i.e., OVCAR-3 and SK-OV-3, are capable for adenoviral transduction judged by LacZ reporter gene analysis, two cell lines demonstrated quite different sensitivities toward AdLPCD/5-FC system. In OVCAR-3 cells, infection of AdLPCD followed by exposure to 5-FC resulted in the suppression of cell growth with statistical significance. On the other hand, SK-OV-3 cells were more resistant to the CD/5-FC strategy compared with OVCAR-3 cells under the same condition. The object of study was to investigate factors that would determine the sensitivity to AdLPCD/5-FC. We evaluated conversion rate of 5-FC to 5-FU after infection of AdLPCD by HPLC analysis, $IC_{50}$ of 5-FU, the expression level of integrin receptors i.e., ${\alpha}v{\beta}3$ and ${\alpha}v{\beta}5$, and status of p53 in OVCAR-3 and SK-OV-3 cells. The results indicated that OVCAR-3 cells have few favorable features compared with SK-OV-3 cells to be more effective to the AdLPCD/5-FC strategy; higher level of ${\alpha}v{\beta}5$ integrin, higher rate of conversion of 5-FC into 5-FC, and lower $IC_{50}$ of 5-FU. The results suggest that the replacement of 5-FU with CD/5-FC in combination chemotherapy would be less toxic and much greater cytotoxicity than the conventional combination chemotherapy in some patients.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.10
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• pp.543-553
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• 2020

This paper examines the effect of COVID-19 pandemic on the Philippine stock exchange, peso-dollar rate and retail price of diesel using robust least squares regression and vector autoregression (VAR). The robust least squares regression using MM-estimation method concluded that COVID-19 daily infection has negative and statistically significant effect on the Philippine stock exchange index, peso-dollar exchange rate and retail pump price of diesel. This is consistent with the results of correlation diagnostics. As for the VAR model, the lag values of the independent variable disclose significance in explaining the Philippine stock exchange index, peso-dollar exchange rate and retail pump price of diesel. Moreover, in the short run, the impulse response function confirmed relative effect of COVID-19 daily infections and the variance decomposition divulge that COVID-19 daily infections have accounted for only minor portion in explaining fluctuations of the Philippine stock exchange index, peso-dollar exchange and retail pump price of diesel. In the long term, the influence levels off. The Granger causality test suggests that COVID-19 daily infections cause changes in the Philippine stock exchange index and peso-dollar exchange rate in the short run. However, COVID-19 infection has no causal link with retail pump price of diesel.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.5
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• pp.569-573
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• 1995

This experiment was carried out to investigate the effect of Azukibean seeds gained from virus-infected plant on the growth and yield of the next generation. In conventional cultivation, plants showed high infection rate, whereas plants in isolation cultivation showed normal growth without virus-infection. It was considered that virus-infection of Azukibean(variety Chungjupat) occurred not because of seed infection but because of insects-vector in growing period. And thread-shaped virus particles were observed in diseased leaf showing mosaic through electron microscope.

• Korean Journal Plant Pathology
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• v.1 no.2
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• pp.109-114
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• 1985

The experiments were conducted to clarify the influence of transplanting date on the occurrence of rice virus in field condition of 1984. The rate of RBSDV (rice black-slreaked dwarf virus) viruliferous vector, smaller brown planthopper (Laodelphax striatellus Fallen), was shown to be $13.6\%$ at the 2nd adult and that of rice stripe virus (RSV) viruliferous was $6.7\%$ at the 2nd adult. The vector in the field was begun to come from May 29, the maximum densities were 19.6 insects per hill on June 13 in cultivar Chucheongbyeo, 19.3 in Nagdongbyeo, 7.4 in Cheongcheongbyeo and 4.9 in Samgangoyes. The number of vectors per hill was inclined to increase by early transplanting. Although the infection of rice virus in nursery bed was not recognized until May 30 transplanting, the nursery infection could be seen from June 10 transplanting. The highest rate of nursery infection with RSV was $4.1\%$ at June 10 transplanting plot, and that of RBSDV was $14.2\%$at June 20 trans planting plot. The infection of rice virus in paddy field was the highest at May 20 transplanting plot, the lowest at July 10 plot. The earlier transplanting, the more severe occurrence of rice viruses. Occurrence of infected plants with RBSDV was shown to increase more rapidly at May 20 and May 30 planting plot than May 10 plots. However, the occurrence of infected plant with RSV was more rapid at May 10 transplanting plot than May 20 and 30.

• Korean journal of applied entomology
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• v.54 no.4
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• pp.419-423
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• 2015

Small brown planthopper (SBPH), Laodelphax striatellus, gives a lot of damage to the rice by insect vector of rice stripe virus (RSV). This study compared the RSV acquisition and infection rates according to wing form, sex, and life stage of SBPH. The RSV acquisition rate in macropterous and brachypterous was 60.7% and 63.1%, respectively. The RSV acquisition rate by sex was 61.9% in female and 52.2% in male. However, there was no difference in significance. The RSV acquisition rate of nymphs and adults was 51.2% and 58.7%, respectively. The RSV infection rate by wing form was 53.3.% in macropterous and 48.2% in brachypterous. According to life stage, nymphs was 38.2% and adults was 42.6%. There was no difference in significance. On the other hand, female and male of RSV infection rate was 50.5% and 22.3%, respectively. There was a significant difference. Additionally, developmental periods of SBPH by RSV infection, the longest when inoculated with RSV-infected SBPH in healthy rice, while the shortest when inoculated healthy SBPH in healthy rice.

• Journal of Ginseng Research
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• v.10 no.1
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• pp.45-54
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• 1986

These studies were carried out to obtain the basic information about transformation of ginseng plant by potential vector system, utilization of opine compound by Agrobacterium sap. , and initiation of crown gall tumor callus. Crown gall tumors were induced from stem of Panax ginseng C.A. Meyer by infection of Agrobacterium tumefaciens. Therefore, it was clarified that transformation of ginseng by Ti plasmid was possible. The crown gall tumors induced by Agrobacterium tumefaciens isolated. from the soil were different in a shape, size, and growth rate. Especially, infection of ginseng by Agrobacterium tumefaciens Y104 led to the amorphic tumor, Tumor tissue derived from stem crown gall could not be continuously cultured on the medium which did not contain phytohormone, and did not form the callus even on the medium supplemented with 2,4-D. On the other hand, the root crown gall tumors formed the calli but the formation rate of callus was quite low. As for the utilization of octopine and nopaline, it was found that 3 strains of Agrobacterium app., Y104, Y110 and C58, utilized nopaline only, Y109 utilized octopine, and Y101 failed to utilize either compound.

• Parasites, Hosts and Diseases
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• v.29 no.1
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• pp.87-92
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• 1991

In order to determine the vector species of tsutsugamushi disease in Korea chiggers were individually dissected, and internal contents were tested for Rickettsia tsutsugamushi organisms by means of indirect FA test, and each exoskeleton was mounted on slide for identification. Among 4,142 chiggers collected from 48 Apodemus agrarius at nine different localities during the period of July-November, 1989, 990 chiggers of 10 species of Trombiculidae were dissected and tested. Rickettsiae were confirmed in two Leptotrembidium pallidum larvae out of 447 tested, giving 0.4% of the infection rate. The chiggers of the other species tested were found negative.

• Korean Journal of Animal Reproduction
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• v.19 no.1
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• pp.35-41
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• 1995

In this study, we have tested whether the retrovirus vector system is applicable in transgenic cattle production. To overcome low infectivity of currently available retrovirus vector system we have directly microinjected retrovirus-producing cells into the perivitelline space of the day 1.5 embryos. The virus-producing cell line was designed to release replication-defective retrovirus encapsidated with Gibbon ape leukemia virus (GaLV) envelope protein. E. coli LacZ gene was used as a marker gene to facilitate evaluation of the transgene expression and X-gal staining at morula or blastocyst stage resulted in expression of E. coli LacZ gene The results in these experiments were summarized as follows : 1. The lowest concentration of polybrene necessary for efficient virus infection was Sf' g/ml. 2. Development rate from day 1.5 embryos microinjected with virus-producing cells to the morulae /blastocysts was 29%. 3. 21% of the morulae /blastocysts were LacZ+. 4. There was no evidence that the retrovirus-producing cells used in this study produced replication-competent retrovirus.

• The Plant Pathology Journal
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• v.33 no.6
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• pp.608-613
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• 2017

The full-length sequence of a new isolate of Apple chlorotic leaf spot virus (ACLSV) from Korea was divergent, but most closely related to the Japanese isolate A4, at 84% nucleotide identity. The full-length cDNA of the Korean isolate of ACLSV was cloned into a binary vector downstream of the bacteriophage T7 RNA promoter and the Cauliflower mosaic virus 35S promoter. Chenopodium quinoa was successfully infected using in vitro transcripts synthesized using the T7 promoter, detected at 20 days post inoculation (dpi), but did not produce obvious symptoms. Nicotiana occidentalis and C. quinoa were inoculated through agroinfiltration. At 32 dpi the infection rate was evaluated; no C. quinoa plants were infected by agroinfiltration, but infection of N. occidentalis was obtained.