• Parasites, Hosts and Diseases
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• 제45권2호
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• pp.87-94
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• 2007

In this study, we describe Korean isolates of Trichomonas vaginalis infected with double-stranded (ds) RNA virus (TVV). One T. vaginalis isolate infected with TVV IH-2 evidenced weak pathogenicity in the mouse assay coupled with the persistent presence of a dsRNA, thereby indicating a hypovirulence effect of dsRNA in T. vaginalis. Cloning and sequence analysis results revealed that the genomic dsRNA of TVV IH-2 was 4,647 bp in length and evidenced a sequence identity of 80% with the previously-described TVV 1-1 and 1-5, but only a 42% identity with TVV 2-1 and 3 isolates. It harbored 2 overlapping open reading frames of the putative capsid protein and dsRNA-dependent RNA polymerase (RdRp). As previously observed in the TVV isolates 1-1 and 1-5, a conserved ribosomal slip-page heptamer (CCUUUUU) and its surrounding sequence context within the consensus 14-nt overlap implied the gene expression of a capsid protein-RdRp fusion protein, occurring as the result of a potential ribosomal frameshift event. The phylogenetic analysis of RdRp showed that the Korean TVV If-2 isolate formed a compact group with TVV 1-1 and 1-5 isolates, which was divergent from TVV 2-1, 3 and other viral isolates classified as members of the Giardiavirus genus.

• The Plant Pathology Journal
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• 제24권2호
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• pp.152-158
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• 2008

A peculiar virus-like disease of tomato showing yellow mosaic and necrotic spots on leaves and necrosis on veins, petioles and stems was observed at the Tomato Experimental Station (TES), Buyeo, Chungcheongnamdo, Korea. The disease incidence at TES fields ranged from 21 to 35% infecting different tomato cultivars. For this reason, to identify the virus infecting tomato and to characterize the virus based on biology, serology, cytology and at molecular level. Here, leaf samples were randomly collected from different infected tomato cultivars at TES fields and greenhouses and tested by ELISA using Pepper mottle virus (PePMoV) and Tomato mosaic virus (ToMV) antisera. Infected saps were mechanically inoculated in different host plants to test for pathogenicity, symptomatology and host ranges. Infected tissues and ultrathin sections were examined by electron microscopy. Finally, putative coat protein and 3'-untranslated region (CP/3'-UTR) fragment was amplified and cloned for sequence determination and analyzed its genetic relationship to existing PepMoV and PVY sequences at the Genbank. Results showed 69% of the samples were positive with PepMoV, 13% with ToMV and 19 % were doubly infected with PepMoV and ToMV. Symptoms greatly varied from different host plants inoculated with tomato leaf sap infected with PepMoV alone and discussed in detailed in this paper. Electron microscopy from infected tissues showed filamentous particles of 720-750nm in length, a typical morphology and size of PepMoV. In addition, cylindrical inclusion bodies, pinwheels, scrolls and laminates with masses of fibrillar inclusions were also found in ultrathin sections. Alignment of the sequences of the CP/3'-UTR revealed >96% sequence identity with PepMoV and only <61% with PVY. Taken together, all these evidences presented clearly indicated that the causal agent infecting tomato at TES was PepMoV and we designated this PepMoV infecting tomato as Tom-sd2 strain in this study.

• 한국응용곤충학회지
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• 제29권4호
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• pp.244-251
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• 1990

담배거세미나방 핵다각체병바이러스에 섭식촉진물질, 다각체 침전방지제 및 전착물질과 자외선 차단제를 첨가하여 만든 3종의 바이러스 살충제를 담배거세미나방 유충에 먹여 제제별로 살충 효과를 비교하였다. 바이러스 살충제에 설탕농도 1-5% 첨가로 섭식촉진이 증대되어 살충효과가 높았으며, 바이러스의 불활화 차단효과도 있었다. 살충제 제형에 따른 바이러스 침전방지는 polyvinylalcohoI 0.5%, 식물체 전착성은 Triton X -100 0.1 %에서 효과가 좋았다. 자외선차단제의 양은 white carbon은 100 L 당 800 g, molasses는 30%첨가에서 바이러스의 불활화가 감소되었으며 white carbon-molasses 혼합제는 white carbon 500 g, molasses 10%의 비율에서는 살충효과가 약간 감소하였으나 세 제제 모두 살포 3일후 95%이상의 살충율을 보였다. White carbon 체제는 molasses 제제보다 다각체 포매가 뚜렷하여 잔류효과가 증대되었으나 유충의 섭식은 molasses제제에서 촉진되었다.

• 대한수의학회지
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• 제42권2호
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• pp.241-251
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• 2002

Modified-live (ML) infectious laryngotracheitis (ILT) vaccines have been widely used as a preventive measure in Korea since the first outbreak of ITL. Recently, it has been observed that chickens vaccinated with the commercially available ML ILT vaccine have sometimes exhibited adverse clinical signs. In this study, we evaluated the quality of the vaccines by comparing titer of each vaccine batch and testing the stability of ILT virus (ILTV) in vaccine diluents and compared the safety and efficacy of vaccines in specific pathogen free (SPF) chickens. The ratio of maximum titer to minimum titer of vaccine produced by most manufacturers was 2 to 15. However, 2 out of 11 manufacturers produced vaccines of which the ratio was 74 to 478. Most vaccines examined were maintained vaccine titers suitable for national regulations within expiry date. However, some vaccines did not keep the titer required for the national regulations. In the test for stability of ILTV in various diluents, ILTV was highly stable in lactose-phosphate-glutamine-gelatin solution, sucrose-phophate-glutamine-albumin solution and some vaccine diluents produced by manufacturers. The safety of ML ILT vaccines was assessed in 10-day-old SPF chicks. Mortality in SPF chicks inoculated intratracheally with one dose of vaccine varied depending on vaccines and some vaccines produced 50-85% mortality. Seven-week-old SPF chickens were vaccinated intraocularly with ML ILT vaccines and then challenged intratracheally with ILT challenge virus 14 days after vaccination. The protection rate was assessed by clinical signs and reisolation of the ILT challenge virus from tracheas taken at day 4 after challenge. There were slight respiratory reactions in some vaccinated chickens after vaccination but these reactions disappeared within 5 days after vaccination. No further clinical signs and death were observed. Protection rate determined by clinical signs and mortality was 100% in all vaccinated groups. However, the challenge virus was isolated from all tracheas of chickens vaccinated with vaccine B or control groups. The challenge virus was also isolated in the trachea of one in five chickens vaccinated with either vaccine F or K, but not in tracheas of chickens vaccinated with other vaccines. In the present study, the stability of vaccine diluents, pathogenicity and protection rate based on reisolation test of the challenge virus were different depending on vaccines produced by eleven manufacturers.

• 한국가금학회지
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• 제19권2호
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• pp.65-76
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• 1992

Since the first outbreaks of Newcastle disease ( ND) in Korea was reported in 1927, the disease has been a major problem in Korean poultry industry. Several attempts related ND prevention and controls have been tried and significantly reduced the ND outbreaks. However, recently frequencies of ND outbreaks have been increased throughout the country since 1988. Many assumptions such as variances of ND virus pathogenicity, decreased efficacy of ND vaccine, incorrect vaccination program etc, has been issued and discussed. Therefore, to clearly understand this recent situation of ND outbreaks in Korea, we reviewed all available past informations related with ND outbreaks in Korea and compared the virulence of recently isolated ND viruses with that of a reference one. Also, we discussed about some problems related with serological diagnosis. administration methods of vaccine and vaccination program.

• IMMUNE NETWORK
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• 제16권5호
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• pp.261-270
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• 2016

The human immune system has evolved to fight against foreign pathogens. It plays a central role in the body's defense mechanism. However, the immune memory geared to fight off a previously recognized pathogen, tends to remember an original form of the pathogen when a variant form subsequently invades. This has been termed 'original antigenic sin'. This adverse immunological effect can alter vaccine effectiveness and sometimes cause enhanced pathogenicity or additional inflammatory responses, according to the type of pathogen and the circumstances of infection. Here we aim to give a simplified conceptual understanding of virus infection and original antigenic sin by comparing and contrasting the two examples of recurring infections such as influenza and dengue viruses in humans.

• 한국가금학회지
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• 제18권3호
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• pp.141-150
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• 1991

국내에서 분리된 CAA의 병아리에 대한 병원성시험과 야외계군에서의 CAA에 대한 항체 보유상황을 조사한 결과 다음과 같은 결론을 얻었다. 1. CAA국내 분리주 89-69를 감수성이 있는 1일령의 SPF병아리에 접종하였을 때 접종 14일 후 심한 빈혈과 흉선 및 Fabricius낭의 위축이 유발되었고 접종계 및 그 동거계에서 CAA가 재분리되었다. 2. CAA분리주 89-69를 유래가 다른 1일령의 SPF 두 계군의 병아리에 각각 근육접종하였을 때 두 계군간 CAA분리주에 대한 감수성의 차이를 보여 주었으며 이는 이 두 계군에서의 CAA에 대한 항체보유율과 관련이 있었다. 3. 간접형광항체반응 시험으로 야외계군에서의 CAA에 대한 항체보유상항을 조사한 결과 39계군중 29계군(74％)이 CAA에 대한 항체를 보유한 것으로 나타났으며 두 SPF계군중 한 SPF계군에서도 항체가 검출되었다.

• Journal of Microbiology and Biotechnology
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• 제31권4호
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• pp.529-539
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• 2021

The beet armyworm, Spodoptera exigua, is a serious insect pest infesting various vegetable crops. Two infectious insect viruses, baculovirus and iflavirus, are known to induce epizootics in S. exigua populations. Indeed, some laboratory colonies have appeared to be covertly infected by these viruses. Diagnostic PCR tests detected two different viruses: Spodoptera exigua multiple nucleopolyhedrosis virus (SeMNPV) and iflaviruses (SeIfV1 and SeIfV2). Viral extract from dead larvae of S. exigua could infect Sf9 cells and produce occlusion bodies (OBs). Feeding OBs to asymptomatic larvae of S. exigua caused significant viral disease. Interestingly, both SeIfV1 and SeIfV2 increased their titers at late larval stages. Sterilization of laid eggs with 1% sodium hypochloride significantly reduced SeMNPV titers and increased larval survival rate. Double-stranded RNA (dsRNA) specific to SeIfV1 or SeIfV2 significantly reduced viral titers and increased larval survival rate. To continuously feed dsRNA, a recombinant Escherichia coli HT115 expressing SeIfV1-dsRNA was constructed with an L4440 expression vector. Adding this recombinant E. coli to the artificial diet significantly reduced the SeIfV1 titer and increased larval survival. These results indicate that laboratory colony collapse of S. exigua is induced by multiple viral infections. In addition, either suppression of SeMNPV or SeIfV infection significantly increased larval survival, suggesting a cooperative pathogenicity between baculovirus and iflavirus against S. exigua.

• 농약과학회지
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• 제12권3호
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• pp.283-290
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• 2008

베큘로바이러스는 일부 나비목 해충을 대상으로 방제하는 데 사용되고 있다. 그러나 화학농약에 비해 느린 살충효과 및 좁은 적용 해충으로 응용 범위에 한계를 갖고 있다. 본 연구는 이러한 한계를 극복하고자 곤충의 면역억제을 통해 바이러스 병원력을 제고시킬 수 있는 기술을 소개한다. 폴리드나바이러스는 일부 맵시벌 및 고치벌에 공생하는 곤충 DNA 바이러스 분류군이다. 프루텔고치벌(Cotesia plutellae) 유래 CpBV(Cotesia plutellae bracovirus)는 브라코바이러스에 속한 폴리드나바이러스로서 면역어제를 발휘하는 여러 유전자를 함유하고 있다. 이 가운데 7개의 CpBV유전자를 선발하고 이를 야생형Autographa California multiple nucleopolyhedrovirus(AcNPV)에 재조합하였다. 이들 재조합 베큘로바이러스를 이용하여 파밤나방(Spodoptera exigua)과 배추좀나방(Plutella xylostella)을 대상으로 생물 검정한 결과, 이들 대부분은 야생형의 바이러스와 유사하거나 우수한 살충력을 나타냈다. 특히 CpBV-ELP를 포함한 재조합 베큘로바이러스가 대조바이러스에 비해 살충시간을 약 2 일 이상단축시킴으로 가장 우수하였다. 이 재조합 베큘로바이러스는 농도에 따른 살충력증가와 배추를 가해하는 파밤나방을 대상으로 한 바이러스 살포 처리가 뚜렷한 방제효과를 나타내어 현장 적용 가능성을 제시하였다. 또한 본 연구는 이 재조합 바이러스의 살충력 제고 현상을 CpBV-ELP의 항바이러스 기작 억제라는 측면에서 고찰했다.

• 한국어병학회지
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• 제11권2호
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• pp.97-104
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• 1998

1989년부터 남해안 일원 해상 가두리 양식장에서 사육중이던 능성어가 고수온기에 대량폐사하여 폐사율이 80%이었다. 발병한 병어는 채색흑화, 안구돌출, 평행감각 상실,회전운동과 몸통이 휘어지는 증상을 나타냈고, 조직학적으로는 뇌조직 및 안구망막의 신경세포가 공포 또는 괴사되었다. 병어로 부터 어류주화세포를 이용한 세포배양법으로 원인 바이러스는 분리되지 않았지만, 뇌 신경세포의 세포질에서 크기가 약 30 nm이며 외막(envelop)이 없는 다면체 모양의 바이러스 입자가 전가현미경적으로 관찰 되었다. 능성어로 부터 분리된 바이러스는 에테르나 열($50^{\circ}C$, 30분)처리에 의해 병원성이 실활되지 않았으나, 강산(pH 3)이나 강알카리(pH 11)에는 부분적으로 병원성이 실활되었다. 그리고 fish nodavirus인 Striped Jack Nervous Necrosis Virus(SJNNV)의 primer를 이용하여 인위감염 및 자연감염된 능성어를 대상으로 PCR을 한 결과 감염된 능성어의 뇌 및 안구조직에서 악 430 bp정도의 PCR 증폭산물이 검출되므로서 능성어를 폐사시키는 원인 바이러스는 SJNNV와 아주 유사한 nodavirus 였다.