• Journal of Apiculture
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• v.34 no.3
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• pp.245-254
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• 2019

We investigated the anti-tumor effects and molecular mechanism of Brazil, China and Korean regional propolis on HeLa ovarian cancer cell line. Each propolis extracts was prepared by ethanol extraction method. Cytotoxicity of propolis extracts was determinated by EZ-cytox cell viability assay. To necessity of anti-tumor effect and molecular mechanism of propolis, we must be adjusting propolis concentration. Due to 100 ㎍/mL of propolis extract were reduced cell viability to less than 50%, we adjusted all of propolis concentration to 100 ㎍/mL. By Western blotting analysis, we confirmed that anti-tumor mechanism of Brazil, China and Korea regional propolis has significantly difference. All of propolis was activated apoptosis related molecules such as PARP, caspase-3. However, cell proliferation signaling molecules including Akt1, ERK and Bcl-2 were reduced the protein expression level. Especially, the expression of tumor suppressor protein p53 was significantly increased in propolis-treated group such as Gyeonggi, Chungbuk, Chungnam, Jeonbuk, Gyeongnam and China. The phosphorylation of Bax which as apoptosis indicator was appeared in propolis-treated group such as Gyeonggi, Gangwon, Chungnam, Gyeongbuk, China. In this results showed that the regional propolis has completely different mechanism in anti-tumor. Thus, propolis extracts may be useful source of functional materials on anti-cancer and it will be able to choose the suitable propolis for cancer therapy by analyzing individual characteristics.

• Journal of Life Science
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• v.18 no.8
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• pp.1023-1030
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• 2008

NtMEK2, which is the tobacco MAPK kinase that is upstream of SIPK and WIPK, was identified using the dexamethasone (DEX)-inducible gain-of-function transgenic system. Expression of $NtNEK2^{DD}$, a constitutively active mutant of NtNEK2, leads to HR-like cell death, which indicates that the NtMEK2-SIPK/WIPK cascade controls defense responses in tobacco. However, little is known about the downstream target substrates or defense-related genes that are regulated by the NtMEK2-SIPK/ WIPK cascade. In this study, ACP-based differential display RT-PCR was used to isolate the downstream effectors mediated by the NtMEK2-SIPK/WIPK cascade in $NtNEK2^{DD}$ transgenic plants. The results identified 6 novel differentially expressed genes (DEGs). These included pathogen induced protein 2-4 (pI2-4), monoterpene synthase 2 (MTS2), seven in absentia protein (SINA), cell death marker protein 1 (CDM1), hydroxyproline-rich glycoprotein (HRGP) and unknown genes (DEG45). The induction of these genes was confirmed by RT-PCR of samples obtained from $NtNEK2^{DD}$ plants. Additionally, when compared with other isolated DEGs, the pI2-4, CDM1 and HRGP genes were significantly up-regulated in response to treatment with salicylic acid and tobacco mosaic virus. Taken together, these results suggest that three novel DEGs were regulated by the NtMEK2-SIPK/WIPK cascade involved in disease resistance in tobacco.

• Korean Journal of Microbiology
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• v.49 no.1
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• pp.64-70
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• 2013

The greenhouse whitefly, Trialeurodes vaporariorum, is an economically important pest for greenhouse crops because they cause direct damage by feeding on plant nutrients and indirect damage as transmits many virus vectors. It has recently become a serious problem because of the continuous use of insecticide resulting in resistance among greenhouse whitefly population. To overcome these problems, in this study, the biological characteristics and virulence of an entomopathogenic fungus isolated from the cadaver of nymph greenhouse whitefly were investigated. Isolated fungus was identified as Isaria fumosorosea by morphological examinations and genetic identification using sequences of the ITS, ${\beta}$-tubulin, and EF1-${\alpha}$ regions. This fungus was named as I. fumosorosea SDTv and tested for the virulence against nymphs T. vaporariorum and the cold activity, the thermotolerance and the stability of UV-B irradiation on conidia. Mortality rate of greenhouse whitefly showed from 84 to 100% and the virulence increased with increasing conidial concentrations, $1{\times}10^5$ to $10^8$ conidia/ml. Conidia were stable at $35^{\circ}C$, 0.1 $J/cm^2$ of UV irradiation and germinated after 8 days at $4^{\circ}C$. Additionally, the activities of chitinases and proteases produced by I. fumosorosea SDTv were varied according to the medium. In conclusion, I. fumosorosea SDTv which showed high mortality rate against greenhouse whitefly will be used effectively in the integrated pest management programs against the greenhouse whitefly.

• Journal of The Korean Association For Science Education
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• v.36 no.2
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• pp.203-219
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• 2016

The purpose of this paper was analyzing the contents of life science area in elementary science textbooks according to Korean science curricula change to get suggestions for the advancement of science curriculum. The framework of content analysis was developed by revising TIMSS 2015 life science evaluation framework. The results of this research were as follows: 'The differences of living things and non-living things appearing in the first grade mostly were not included in the 1st, the 6th and the 2009 revised curricula. Contents emphasizing rural life were appeared from 'Teaching themes period' to the 2nd curriculum period, disappeared from the 3rd curriculum period until the 2009 revised curriculum. Contagious disease was emphasized in all elementary grades in the 1st curriculum period, which reflected a social phenomena emphasizing health and hygiene after the Korean War. Mostly fungus was included until the 7th curriculum period and bacteria and virus were added from the 2007 revised curriculum period. The way of improving health was emphasized continuously.' The differences of living things and non-living things should be included in elementary science curriculum for the correct 'life' concept formation of elementary students. 'Strategies for helping the living of descendants' and 'the heredity of animal and plant' which were appeared in the lower grades, should be included at the higher grades with greater depth. The incoming elementary science textbooks also need to include science contents about evolution in greater depth, along with human health.

• Journal of Life Science
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• v.20 no.2
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• pp.190-196
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• 2010

Nowadays many people use antibiotics to protect processed foods from many pathogenic bacteria. The abuse of antibiotics, however, can run the risk of creating resistant forms of bacterium. Our study focus is on making new substances that can not only replace antibiotics but also be friendly to the environment. In our experiments, we used fermented citrus fruit, soil microbes and coenzyme Q10 as probiotics and prebiotics. Chickens in the experimental group were fed these substances via oral route while those in the control group were not. After specific time periods, blood and feces samples were collected to test for Salmonella spp.. It is interesting that fermented citrus fruit was the most effective in suppressing this bacterium. Furthermore, dissection of the experiment group chickens shows that their livers did not change to a yellow color, in contrast to the control group. The results confirmed our proposal that the chickens fed with these materials can be protected from infection by Salmonella and other pathogens. These probiotics and prebiotics are highly practical because they are natural substances that can be easily recycled in the environment. It can also be used as an animal feed ingredient because of its safety.

• Horticultural Science & Technology
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• v.31 no.2
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• pp.246-254
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• 2013

Five isolates of Tomato yellow leaf curl virus (TYLCV) collected from various regions of Korea were amplified using PCR and determined the sequences of full-length genome, respectively. The PCR-amplified DNA of each TYLCV isolate was introduced into a binary vector to construct infectious clone containing 1.9 copies of the corresponding viral genome. Various cultivars and breeding lines of tomato were inoculated with Agrobacterium tumefaciens harboring infectious clone of each TYLCV isolate to assess resistance against TYLCV. Susceptible cultivar 'Super-sunread' revealed typical yellowing and narrowing of the upper leaves. In contrast, breeding linesTY12, GC9, GC171, and GC173, which contained the TY-1 and/or TY-3 genes that confer resistance against TYLCV in nature, were completely symptomless, suggesting that the lines were resistant to challenging TYLCV isolates. Symptoms of TYLCV in susceptible tomato cultivars are significantly different from those of TYLCV in the resistant tomato cultivars at 30 days after agroinfiltration. Although genomic DNAs of TYLCV were detected from the breeding lines TY12, GC9, GC171, and GC173 using real-time PCR analysis with specific primers, levels of TYLCV DNA accumulation in the resistant breeding lines were much lower than those of TYLCV DNA accumulation in susceptible tomato cultivars. Similar symptom severity and levels of TYLCV DNA accumulation were observed from TYLCV infections mediated by Bemisia tabaci in the resistant and susceptible tomato cultivars. Concentration of agrobacterium did not affect the response of tomato cultivars against TYLCV inoculation. Taken together, these results suggest that TYLCV inoculation via agroinfiltration is as effective as inoculation through Bemisia tabaci and is useful for breeding programs of TYLCV-resistant tomato.

• Korean Journal of Microbiology
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• v.48 no.4
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• pp.284-292
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• 2012

To date, chemical control remains the most common way to reduce beet armyworm (Spodoptera exigua) populations. However, this insect has become more tolerant or resistant to many chemical insecticides and the insect larvae usually hide inside hollow, tube-like leaves of host plant so they were difficult to kill by spraying insecticides. The use of viral and bacterial insecticide to solve these problems has not been successful because of their novel feeding habit. To overcome these problems, in this study, the biological characteristics and virulence of an entomopathogenic fungus isolated from the cadaver of larvae beet armyworm were investigated. Isolated entomopathogenic fungus was identified as Nomeraea rileyi (Farlow) Samson by morphological examinations and genetic identification using sequences of the ITS, ${\beta}$-tubulin gene and EF1-${\alpha}$ regions. This fungus was named as N. rileyi SDSe. Virulence tests against 3rd larvae of beet armyworm were conducted with various conidial suspensions from $1{\times}10^4$ to $10^8$ conidia/ml of N. rileyi SDSe in laboratory conditions. Mortality rate of beet armyworm showed from 20 to 54% and the virulence increased with increasing conidial concentrations. Although N. rileyi SDSe showed low mortality rate against beet armyworm, it is expected that N. rileyi SDSe will be used effectively in the integrated pest management programs against the beet armyworm.

• Korean Journal of Breeding Science
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• v.49 no.3
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• pp.235-244
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• 2017

'Manbaek' is a bacterial blight resistant mid-late maturing rice cultivar with high grain quality. 'Manbeak' was derived from anther culture using the backcross combination, $Hopum^*2/SR30075$. 'Hopum' is a mid-late maturing rice cultivar with high grain quality and 'SR30075' is a pyramid line carrying three bacterial blight resistance genes. 'Manbaek' was selected through the pedigree method, yield trials, and local adaptability tests. 'Manbeak' carrying two bacterial blight resistance gene Xa3 and xa5 showed high-level and broad-spectrum resistance against bacterial blight. 'Manbaek' was resistant to K3a, mostly virulent race in Korea, and exhibited resistance reaction against 16 Korean bacterial blight isolates. 'Manbaek' was a mid-late maturing rice. The heading date of 'Manbaek' was August 19th, which was 5 days later than that of 'Nampyeong'. Manbaek' was a lodging-tolerant rice with short culm and dark green leaf. Due to the low viviparous germination, 'Manbaek' could be a useful material to prevent pre-harvest sprouting. 'Mabeak' was resistant to bacterial blight and rice stripe virus, but susceptible to other virus diseases and insect pests. The yield of 'Manbaek' was similar to 'Nampyeong'. 'Manbaek' showed excellent grain appearance and good tastes of cooked rice, so that it could contribute to improving the quality of bacterial blight resistant cultivars. 'Manbaek', bacterial blight resistant cultivar with high grain quality, is suitable for the cultivation at bacterial blight prone area and has been utilized in the breeding programs for enhancing the resistance against bacterial blight (Registration No. 6069).

• Journal of Food Hygiene and Safety
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• v.34 no.1
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• pp.1-12
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• 2019

The health benefits associated with consumption of fresh produce have been clearly demonstrated and encouraged by international nutrition and health authorities. However, since fresh produce is usually minimally processed, increased consumption of fresh fruits and vegetables has also led to a simultaneous escalation of foodborne illness cases. According to the report by the World Health Organization (WHO), 1 in 10 people suffer from foodborne diseases and 420,000 die every year globally. In comparison to other processed foods, fresh produce can be easily contaminated by various routes at different points in the supply chain from farm to fork. This review is focused on the identification and characterization of possible sources of foodborne illnesses from chemical, biological, and physical hazards and the applicable methodologies to detect potential contaminants. Agro-chemicals (pesticides, fungicides and herbicides), natural toxins (mycotoxins and plant toxins), and heavy metals (mercury and cadmium) are the main sources of chemical hazards, which can be detected by several methods including chromatography and nano-techniques based on nanostructured materials such as noble metal nanoparticles (NMPs), quantum dots (QDs) and magnetic nanoparticles or nanotube. However, the diversity of chemical structures complicates the establishment of one standard method to differentiate the variety of chemical compounds. In addition, fresh fruits and vegetables contain high nutrient contents and moisture, which promote the growth of unwanted microorganisms including bacterial pathogens (Salmonella, E. coli O157: H7, Shigella, Listeria monocytogenes, and Bacillus cereus) and non-bacterial pathogens (norovirus and parasites). In order to detect specific pathogens in fresh produce, methods based on molecular biology such as PCR and immunology are commonly used. Finally, physical hazards including contamination by glass, metal, and gravel in food can cause serious injuries to customers. In order to decrease physical hazards, vision systems such as X-ray inspection have been adopted to detect physical contaminants in food, while exceptional handling skills by food production employees are required to prevent additional contamination.