• Parasites, Hosts and Diseases
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• 제57권2호
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• pp.161-166
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• 2019

This study was done to characterize distribution of Rickettsia spp. in ticks in the northwestern and southwestern provinces in the Republic of Korea. A total of 2,814 ticks were collected between May and September 2009. After pooling, 284 tick DNA samples were screened for a gene of Rickettsia-specific 17-kDa protein using nested PCR (nPCR), and produced 88 nPCR positive samples. Of these positives, 75% contained 190-kDa outer membrane protein gene (ompA), 50% 120-kDa outer membrane protein gene (ompB), and 64.7% gene D (sca4). The nPCR products of ompA, ompB, and sca4 genes revealed close relatedness to Rickettsia japonica, R. heilongjiangensis, and R. monacensis. Most Rickettsia species were detected in Haemaphysalis longicornis. This tick was found a dominant vector of rickettsiae in the study regions in the Republic of Korea.

• Entomological Research
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• 제48권5호
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• pp.384-389
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• 2018

Aphis gossypii Glover is an important insect pest that functions as a viral vector and mediates approximately 45 different viral diseases. As part of a strategy for control of A. gossypii, we investigated the functions of genes using RNAi. To this end, a cDNA library was constructed for various genes and for selecting appropriate targets for RNAi mediated silencing. The cDNA library was constructed using the Gateway cloning system with site-specific recombination of bacteriophage ${\lambda}$. It was used to carry out single step cloning of A. gossypii cDNAs. As a result, a cDNA library with a titer of $8.4{\times}10^6$ was constructed. Since the sequences in this library carry att sites, they can be cloned into various binary vectors. This library will be of value for various studies. For later screening of selected genes, it is planned to clone the library into virus-induced gene silencing (VIGS) vectors, which makes it possible to analyze gene function and allow subsequent transfection of plants. Such transfection experiments will allow testing of RNAi-induced insecticidal activity or repellent activity to A. gossypii, and result in the identification of target genes. It is also expected that the constructed cDNA library will be useful for analysis of gene functions in A. gossypii.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2000년도 추계학술발표대회
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• pp.78-82
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• 2000

The AIDS epidemic continues unabated in many part of the world. After near two decades, no vaccine is available to combat the spread of this deadly disease. Much of the HIV -1 vaccine effort during the past decade has focused on the viral envelope glycoprotein, largely because it is the only protein that can elicit neutralizing antibodies (Nabs). Eliciting broadly cross-reactive Nabs has been a primary goal. The intrinsic genetic diversity of the viral envelope, however, has been one of the major impediments in vaccine development. We have recently completed a comprehensive study examining whether it is possible to elicit broadly acting Nabs by immunizing monkeys with mixtures of envelope proteins from multiple HIV -1 isolates. We compared the humoral immune responses elicited by vaccination with either single or multiple envelope proteins and evaluated the importance of humoral and non-humoral immune response in protection against a challenge virus with a homologous or heterologous envelope protein. Our results show that (1) Nab is the correlate of sterilizing immunity, (2) Nabs against primary HIV -1 isolates can be elicited by the live vector-prime/protein boost approach, and (3) polyvalent envelope vaccines elicit broader Nab response than monovalent vaccines. Nonetheless, our findings clearly indicate that the increased breadth of Nab response is by and large limited to strains included in the vaccine mixture and does not extend to heterologous non-vaccine strains. Our study strongly demonstrates how difficult it may be to elicit broadly reactive Nabs using envelope proteins and sadly predicts a similar fate for many of the vaccine candidates currently being evaluated in clinical trials. We have started to evaluate other vaccine candidates (e.g. genetically modified envelope proteins) that might elicit broadly reactive Nabs. We are also exploring other vaccine strategies to elicit potent cytotoxic T lymphocyte responses. Preliminary results from some of these experiments will be discussed.

• Journal of Plant Biotechnology
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• 제31권4호
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• pp.285-293
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• 2004

FMDV는 동물에서 구제역을 일으키는 병원체이며, VP1은 이 바이러스의 주요 capsid단백질이므로 구제역의 진단과 단백질 백신의 개발에 가장 많이 사용되는 재료 중 하나이다. 본 연구는 FMDV taiwan O형과 베트남에서 분리된 FMDV의 VP1 sequence를 기반으로 식물에서 VP1 유전자의 발현을 위하여 633 bp의 VP1유전자로 재편집하였으며, 이를 long-nucleotide를 사용한 multiple fragment extension 방법을 사용하여 인공적인 DNA 단편을 합성하였다. 또한 새로운 식물 형질전환 벡터로 pBI121 과 pCAMBIA1390의 장점을 수용하여, hygromycin 저항성과 CaMV 35S promoter를 포함하는 pCAMBIA II를 제작하였다. 제작된 벡터와 VP1 유전자 및 GFP유전자를 사용하여 담배를 형질 전환시켰고, 각각의 형질전환식물체내에서 전체길이의 target gene(VPl)의 성공적인 삽입을 확인하였다. 각 유전자의 발현은 RT-PCR과 Real-Time PCR의 결과로 측정하였으며, VP1 유전자의 전사가 담배 내에서 이루어졌음과 고효율의 전사체를 만드는 형질전환체 VP1-4를 선별하였다.

• 생명과학회지
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• 제24권9호
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• pp.995-1000
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• 2014

바이러스 분리 및 검출 측면에서의 해양바이러스 연구는 높은 빈도의 돌연변이와 유전적 다양성 때문에 한계가 있어 왔다. 현재 해양바이러스를 검출하기 위해 사용되고 있는 방법 중 ELISA를 기반으로 하는 혈청학적 방법이 가장 보편적이다. 혈청학적 방법은 항체의 질과 고도로 정제된 정확한 항원을 요구한다. 최근에 바이러스 외피단백질을 항원으로 이용하고자하는 새로운 실험시스템이 yeast surface display (YSD)를 사용하여 개발되었다. 이 연구에서는 붉바리 신경괴사 바이러스(RGNNV)의 외피단백질 유전자를 YSD와 HA-tagging 시스템을 이용하여 발현시키고 정제하였다. 2개의 RGNNV 외피단백질 유전자 조각(RGNNV1 및 RGNNV2)을 염기서열 데이터베이스에 기초하여 합성하였고, 효모 발현 벡터인 pCTCON로 클로닝하였다. 효모 strain EBY100에서의 RGNNV 외피단백질의 발현은 발현벡터에 의해 코드되는 C-말단의 c-myc tags를 인지하는 형광표지된 항체를 이용하여 flow cytometry로 검출되었다. 발현된 RGNNV 외피단백질은 ${\beta}$-mercaptoethanol 처리 후 Aga1과 Aga2 사이의 이황화결합 절단에 의해 효모표면으로부터 분리되었다. Anti-HA 항체를 사용한 Western blots을 수행하였을 때 각 RGNNV 외피단백질이 정해진 크기에서 검출되는 것이 확인되었다. 이러한 결과는 YSD와 HA-tagging 시스템이 재조합 RGNNV 외피단백질의 발현과 정제에 적용가능함을 나타낸다.

• The Plant Pathology Journal
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• 제35권4호
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• pp.381-388
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• 2019

For several years, temperatures in the Korean peninsula have gradually increased due to climate change, resulting in a changing environment for growth of crops and vegetables. An associated consequence is that emerging species of insect vector have caused increased viral transmission. In Jeju Island, Korea, occurrences of viral disease have increased. Here, we report characterization of five newly collected turnip mosaic virus (TuMV) isolates named KBJ1, KBJ2, KBJ3, KBJ4 and KBJ5 from a survey on Jeju Island in 2017. Full-length cDNAs of each isolate were cloned into the pJY vector downstream of cauliflower mosaic virus 35S and bacteriophage T7 RNA polymerase promoters. Their fulllength sequences share 98.9-99.9% nucleotide sequence identity and were most closely related to previously reported Korean TuMV isolates. All isolates belonged to the BR group and infected both Chinese cabbage and radish. Four isolates induced very mild symptoms in Nicotiana benthamiana but KBJ5 induced a hypersensitive response. Symptom differences may result from three amino acid differences uniquely present in KBJ5; Gly(382)Asp, Ile(891)Val, and Lys(2522)Glu in P1, P3, and NIb, respectively.

• Journal of Ginseng Research
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• 제47권1호
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• pp.123-132
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• 2023

Background: Pseudotyped virus systems that incorporate viral proteins have been widely employed for the rapid determination of the effectiveness and neutralizing activity of drug and vaccine candidates in biosafety level 2 facilities. We report an efficient method for producing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pseudovirus with dual luciferase and fluorescent protein reporters. Moreover, using the established method, we also aimed to investigate whether Korean Red Ginseng (KRG), a valuable Korean herbal medicine, can attenuate infectivity of the pseudotyped virus. Methods: A pseudovirus of SARS-CoV-2 (SARS-2pv) was constructed and efficiently produced using lentivirus vector systems available in the public domain by the introduction of critical mutations in the cytoplasmic tail of the spike protein. KRG extract was dose-dependently treated to Calu-3 cells during SARS2-pv treatment to evaluate the protective activity against SARS-CoV-2. Results: The use of Calu-3 cells or the expression of angiotensin-converting enzyme 2 (ACE2) in HEK293T cells enabled SARS-2pv infection of host cells. Coexpression of transmembrane protease serine subtype 2 (TMPRSS2), which is the activator of spike protein, with ACE2 dramatically elevated luciferase activity, confirming the importance of the TMPRSS2-mediated pathway during SARS-CoV-2 entry. Our pseudovirus assay also revealed that KRG elicited resistance to SARS-CoV-2 infection in lung cells, suggesting its beneficial health effect. Conclusion: The method demonstrated the production of SARS-2pv for the analysis of vaccine or drug candidates. When KRG was assessed by the method, it protected host cells from coronavirus infection. Further studies will be followed for demonstrating this potential benefit.

• Korean Journal of Radiology
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• 제21권6호
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• pp.726-735
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• 2020

Objective: Recent innovations in biology are boosting gene and cell therapy, but monitoring the response to these treatments is difficult. The purpose of this study was to find an MRI-reporter gene that can be used to monitor gene or cell therapy and that can be delivered without a viral vector, as viral vector delivery methods can result in long-term complications. Materials and Methods: CMV promoter-human organic anion transporting polypeptide 1B3 (CMV-hOATP1B3) cDNA or CMV-blank DNA (control) was transfected into HEK293 cells using Lipofectamine. OATP1B3 expression was confirmed by western blotting and confocal microscopy. In vitro cell phantoms were made using transfected HEK293 cells cultured in various concentrations of gadoxetic acid for 24 hours, and images of the phantoms were made with a 9.4T micro-MRI. In vivo xenograft tumors were made by implanting HEK293 cells transfected with CMV-hOATP1B3 (n = 4) or CMV-blank (n = 4) in 8-week-old male nude mice, and MRI was performed before and after intravenous injection of gadoxetic acid (1.2 µL/g). Results: Western blot and confocal microscopy after immunofluorescence staining revealed that only CMV-hOATP1B3-transfected HEK293 cells produced abundant OATP1B3, which localized at the cell membrane. OATP1B3 expression levels remained high through the 25th subculture cycle, but decreased substantially by the 50th subculture cycle. MRI of cell phantoms showed that only the CMV-hOATP1B3-transfected cells produced a significant contrast enhancement effect. In vivo MRI of xenograft tumors revealed that only CMV-hOATP1B3-transfected HEK293 tumors demonstrated a T1 contrast effect, which lasted for at least 5 hours. Conclusion: The human endogenous OATP1B3 gene can be non-virally delivered into cells to induce transient OATP1B3 expression, leading to gadoxetic acid-mediated enhancement on MRI. These results indicate that hOATP1B3 can serve as an MRI-reporter gene while minimizing the risk of long-term complications.

• 농업과학연구
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• 제45권1호
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• pp.38-42
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• 2018

Demand for tomatoes has been increasing every year as people desire more healthy food. In Korea, tomatoes are mainly grown in the Chungnam, Chunnam and Kyungnam provinces. Recently, reports of whitefly-transmitted viral diseases have increased due to newly emerging whitefly pressures caused by climate change in Korea. Specifically, in 2017, the main tomato growing areas, Buyeo and Nonsan in Chungnam, showed damage typical of viral infection; therefore, we investigated viral diseases in these areas. We collected samples with virus-like symptoms and found that not only whitefly transmitted Tomato yellow leaf curl virus (TYLCV) and Tomato chlorosis virus (ToCV) were detected but also Tomato mosaic virus (ToMV, for which no specific vector is known) and Tomato spotted wilt virus (TSWV, transmitted by thrips). The ToMV-infected samples were mostly co-infected with either TYLCV or ToCV. Mixed infections of different combinations of TYLCV, ToCV and ToMV were detected with the mixed infection of two whitefly-transmitted viruses (TYLCV and ToCV) causing the most severe symptoms. According to the CP sequence of each virus, the 100% identities were shown to be Mexico/ABG73017.1 (TYLCV), Greece/CDG34553.1 (ToCV), China/AKN79752 (TSWV), and Australia/NP078449.1 (ToMV). Based on the sequence data, we presumed that these tomato infecting viruses were transmitted through insects and seeds introduced from neighboring countries.

• 한국동물학회지
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• 제28권3호
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• pp.166-178
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• 1985

한국형 B형 간염바이러스(HBV) DNA의 표면항원 유전자를 포유동물 세포에서 발현시켜 항원의 검출과 유전자의 분자유전학적인 연구를 하기 위하여 pre-surface antigen 지역과 표면항원 유전자 그리고 poly(A) addition site가 포함된 DNA 조각을 simian virus 40(SV 40)의 DNA 복제 원점과 promoter가 포함된 유전자 운반체에 재조함 시켰다. 우선, HBV DNA가 들어있는 pHBV 107을 Bam HI으로 부분절단한뒤 self-ligation시켜 두 HBV DNA가 같은 방향으로 들어간 pHBVD 107을 만들었다. 이 plasmid를 Bgl II로 절단하였을때 pre-surface지역과 표면항원 유전자 그리고 poly(A) addition site가 함께 포함된 2.7 kb의 insert DNA 조각을 얻었다. 유전자 운반체로는 포유동물세포에서 복제할 수 있도록 하기 위하여 SV40의 DNA 복제 원점부위와 72 bp repeats(enhancer)가 포함된 pSVOE를 만든다음 이 vector의 Pvu II 절단자리에 Bam HI linker를 붙여 insert DNA가 vector의 SV40 late promoter지역 가까이에 들어갈 수 있도록 변형시킨 pSVOB를 만들었다. 이상과 같이 만들어진 pre-surface 지역-표면항원유전자-poly(A)-addition site가 포함된 2.7 kb DNA 절편을 pSVOB promoter 뒤의 Bam HI site에 삽입하여 재조합된 plasmid pSVBS를 얻었다. 예비실험으로 pSVBS를 T-antigen이 생산되는 COS cell에 이주시켰더니 $HB_sAg$가 발현됨을 보았다.