• 식물병연구
• /
• 제19권2호
• /
• pp.114-117
• /
• 2013

To facilitate their spread, plant viruses have developed several methods for dispersal including insect and seed transmission. While insect transmission requires virus stability against insect digestion, seed-transmitted viruses have to overcome barriers to entry into embryos. Bean pod mottle virus (BPMV) is transmitted through seed at levels typically below 0.1%, but co-infection with Soybean mosaic virus (SMV) enhanced the seed transmission rate of BPMV in one experiment. In contrast, the rate of SMV seed transmission was not affected by BPMV co-infection. In a second preliminary study, the rate of SMV transmission was lower in an isoline of Williams 82 that contained a null mutation for the Kunitz trypsin inhibitor gene than in Williams 82. In this preliminary study, we observed that factors such as protease inhibitor expression and dual infection may affect the frequency of seed transmission of BPMV and SMV.

• 식물병연구
• /
• 제14권2호
• /
• pp.138-141
• /
• 2008

경상북도 오이 주산단지인 상주와 군위지역의 바이러스 병 발생을 조사한 결과 포장 발생율은 $55.0{\sim}88.6%$였으며, 상주지역이 군위보다 약간 높게 나타났다. 바이러스 발병 포장의 이병주율은 2006년 상주 지역에서 평균 25.6%로 매우 높게 나타났으며, 발생범위는 최소 1.5%에서 최대 90%로 농가별로 편차가 매우 심하였다. 포장에서 바이러스 증상으로 관찰되는 시료 217점을 RT-PCR을 이용하여 바이러스 종류를 분석한 결과 ZYMV가 85% 이상으로 가장 많이 검출되어 오이에 피해를 주는 주요 바이러스로 나타났다. ZYMV에 감염된 오이는 잎에 황화 및 심한 모자이크 증상이 나타났으며 일부 과일은 곡과 증상과 함께 표면이 울퉁불퉁하게 나타났다.

• 식물병연구
• /
• 제18권4호
• /
• pp.298-303
• /
• 2012

토마토황화잎말림바이러스(Tomato yellow leaf curl virus; TYLCV)는 온실가루이(Bemisia tabaci)에 의해서 영속전염되는 DNA 바이러스로 토마토에 발생하는 가장 중요한 병 중 하나이다. 우리나라에서 TYLCV는 2008년 최초로 보고된 이래 급속하게 전국적으로 확산되어 토마토 생산에 심각한 경제적 손실을 일으키고 있다. 토마토 생산과정에서 TYLCV의 확산을 최소화하기 위해 바이러스의 조기진단이 매우 중요하다. 본 연구에서는 바이러스의 신속진단을 위해 초고속 정밀 PCR 진단기술을 개발하였으며, 이는 마이크로칩을 기반으로 하여 $5{\mu}l$의 시료만으로 PCR을 수행할 수 있도록 고안된, 휴대가 가능할 정도의 소형 GenSpector$^{TM}$ TMC-1000 PCR 기기를 이용한 새로운 기술이다. 본 연구에서 개발된 초고속 정량 PCR을 이용하였을 때 TYLCV 진단을 위한 30 cycle의 PCR과 용융점분석(melting curve analysis)에 15분 이내의 시간이 소요되었으며, GenSpector$^{TM}$ TMC-1000 PCR을 이용한 초고속 정밀진단 기술은 향후 TYLCV의 대발생을 모니터링하는데 유용하게 사용될 수 있을 것으로 생각한다. 본 연구결과는 GenSpector$^{TM}$ TMC-1000 PCR기반의 초고속정량 PCR 기술을 이용한 식물 바이러스의 진단기술 개발로는 최초의 보고이다.

• Plant Resources
• /
• 제4권3호
• /
• pp.192-195
• /
• 2001

Human immunodeficiency virus (HIV), the causative agent of AIDS, still continues to spread rapidly in the world population, especially in Africa and Southeast Asia. At present, two kinds of therapeutic approaches are used for treatment of AIDS. One is to target HIV reverse transcriptase, which is responsible for the viral genome transcription. The other is to inhibit HIV pretense PR, which is essential for the processing of viral proteins. Drug combinations based on these approaches can reduce the blood virus to an undetectable level. However, a small amount of virus may lurk inside the immune cells in a dormant state. Another major obstacle of long-term treatment of the disease is remarkable mutation in HIV. Most of the clinical chemotherapeutic agents have one or more of these problems. High cost and harmful side-effects further reduced the desirability of these drugs. In the course our studies on development of anti-HIV agents from natural products, we investigated various crude drugs for their inhibitory activity against HIV-induced cytopathic effects (CPE) in culture cells, HIV-pretense (PR), HIV-reverse transcriptase (RT) including ribonuclease H (RNase H), and HIV integrase (INT). In the present paper, some inhibitory substances relating to the development of anti-HIV agents are reported.

• Journal of Ecology and Environment
• /
• 제46권4호
• /
• pp.276-281
• /
• 2022

Ranaviruses are a primary cause of amphibian extinctions. More consistent ranavirus-infection reports and genetic characterizations of identified viruses are urgently needed, particularly from Asian countries. The objectives of this study were to obtain the partial major capsid protein (MCP) gene sequences (506 bp) of the ranavirus responsible for infecting frogs in South Korea, as our previous research had confirmed using qPCR, and to evaluate their genetic relationships with other previously reported ranavirus sequences. Three different ranavirus MCP sequences were obtained from Pelophylax nigromaculatus and Lithobates catesbeianus. All six different types of MCP sequence from the ranavirus identified in South Korea to date belonged to the Frog virus 3 (FV3)-like virus group in the genus Ranavirus. To better understand the origin and spread of ranaviruses in South Korea, further infection reports and full genome analyses of the identified ranaviruses are needed.

• International Journal of Computer Science & Network Security
• /
• 제24권3호
• /
• pp.107-112
• /
• 2024

Nowadays the deadly virus famous as COVID-19 spread all over the world starts from the Wuhan China in 2019. This disease COVID-19 Virus effect millions of people in very short time. There are so many symptoms of COVID19 perhaps the Identification of a person infected with COVID-19 virus is really a difficult task. Moreover it's a challenging task to identify whether a person or individual have covid test positive or negative. We are developing a framework in which we used machine learning techniques..The proposed method uses DecisionTree, KNearestNeighbors, GaussianNB, LogisticRegression, BernoulliNB , RandomForest , Machine Learning methods as the classifier for diagnosis of covid ,however, 5-fold and 10-fold cross-validations were applied through the classification process. The experimental results showed that the best accuracy obtained from Decision Tree classifiers. The data preprocessing techniques have been applied for improving the classification performance. Recall, accuracy, precision, and F-score metrics were used to evaluate the classification performance. In future we will improve model accuracy more than we achieved now that is 93 percent by applying different techniques

• Journal of Preventive Medicine and Public Health
• /
• 제53권5호
• /
• pp.293-301
• /
• 2020

Objectives: At the beginning of the coronavirus disease 2019 (COVID-19) pandemic, some countries imposed entry bans against Chinese visitors. We sought to identify the effects of border shutdowns on the spread of the COVID-19 outbreak. Methods: We used the synthetic control method to measure the effects of entry bans against Chinese visitors on the cumulative number of confirmed cases using World Health Organization situation reports as the data source. The synthetic control method constructs a synthetic country that did not shut down its borders, but is similar in all other aspects. Results: Six countries that shut down their borders were evaluated. For Australia, the effects of the policy began to appear 4 days after implementation, and the number of COVID-19 cases dropped by 94.4%. The border shutdown policy took around 13.2 days to show positive effects and lowered COVID-19 cases by 91.7% on average by the end of February. Conclusions: The border shutdowns in early February significantly reduced the spread of the virus. Our findings are informative for future planning of public health policies.

• 대한치과의사협회지
• /
• 제54권1호
• /
• pp.67-83
• /
• 2016

Ebola virus disease is a lethal viral hemorrhagic fever that has been boiling in sub-Saharan Africa since 1970s. Last year, The Ebola virus epidemic that has spread not only mainly in West Africa, but also in locals such as USA, Europe and the Antipodes via infected travelers, was brought up. Human-to-human transmission of Ebola virus disease is known only through direct contact with the blood, secretions, tissues or other bodily fluids, including saliva. Although there has not been reported infection cases in the dental healthcare settings, the fact that the infection of the Ebola virus may be made from human secretions such as saliva suggests that there is a high risk of infection for the Ebola virus of dental healthcare workers. Therefore, it is important dental healthcare workers to identify infection-suspected patients through the oral findings for infection prevention. This article will review the oral signs and symptoms of Ebola virus disease and discuss the pathogenesis, treatment and prevention. Furthermore, Infection control guidelines for oral healthcare workers are also proposed.

• 한국동물위생학회지
• /
• 제46권3호
• /
• pp.193-202
• /
• 2023

Porcine epidemic diarrhea is an infectious intestinal disease caused by the porcine epidemic diarrhea virus (PEDV). Especially, when suckling piglets are infected, the mortality rate is close to 100%. PEDV is classified into G1 and G2 types based on genetic differences. The G2 type PEDV outbreak in the United States in 2013 was highly pathogenic and contagious, and it has spread worldwide and caused continuous economic losses. Most commercial vaccines used are G1 type vaccines, and existing vaccines do not fully protect piglets due to genetic differences. In this study, we evaluated the safety of the newly developed G2 type attenuated HSGP vaccine strain by inoculating it into piglets and testing whether the vaccine virus spreads to the non-vaccinated, negative pigs and whether the vaccine reverts to its virulence during serial passage experiments. Each experiment lasted for 7 days for each passage, and fecal viral titers, clinical symptoms, and weight gain were measured daily. After the experiment, necropsy was performed to measure intestinal virus titer and pathological evaluation. As a result of the first passage, no transmission of the vaccine virus to negative pigs co-housed with vaccinated pigs was observed. In addition, after four consecutive passage experiments, the clinical symptoms and small intestine lesions were gradually alleviated, and no virus was detected in the feces in the fourth passage experiment. Therefore, it was concluded that the vaccine was safe without virulence reversion in accordance with the guidelines of the current licensing authority. However, further studies are needed on the genetic changes and biological characteristics of the mutant virus that occur during successive passages of the attenuated vaccine since the replication and clinical symptoms of the virus increased until the third passage during successive passages of the vaccine virus. Based on this study, it was concluded that virulence reversion and safety evaluation of attenuated vaccines through serial passage in target animals can be useful to evaluate the safety of attenuated viruses.

• Journal of Microbiology and Biotechnology
• /
• 제33권12호
• /
• pp.1576-1586
• /
• 2023

Vaccination is the most effective method for preventing the spread of the influenza virus. Cell-based influenza vaccines have been developed to overcome the disadvantages of egg-based vaccines and their production efficiency has been previously discussed. In this study, we investigated whether treatment with forskolin (FSK), an adenylyl cyclase activator, affected the output of a cell-based influenza vaccine. We found that FSK increased the propagation of three influenza virus subtypes (A/H1N1/California/4/09, A/H3N2/Mississippi/1/85, and B/Shandong/7/97) in Madin-Darby canine kidney (MDCK) cells. Interestingly, FSK suppressed the growth of MDCK cells. This effect could be a result of protein kinase A (PKA)-Src axis activation, which downregulates extracellular signal-regulated kinase (ERK)1/2 activity and delays cell cycle progression from G1 to S. This delay in cell growth might benefit the binding and entry of the influenza virus in the early stages of viral replication. In contrast, FSK dramatically upregulated ERK1/2 activity via the cAMP-PKA-Raf-1 axis at a late stage of viral replication. Thus, increased ERK1/2 activity might contribute to increased viral ribonucleoprotein export and influenza virus propagation. The increase in viral titer induced by FSK could be explained by the action of cAMP in assisting the entry and binding of the influenza virus. Therefore, FSK addition to cell culture systems could help increase the production efficiency of cell-based vaccines against the influenza virus.